What Diameter, GTP, MAP, SIP, Q.850 and LTE NAS (EMM/ESM) codes mean in practice, who sends them and what to check — each with the specification it comes from.
| 2001 | DIAMETER_SUCCESS The responding node accepted and fully processed this request -- no error, rejection, or missing data. Whatever this pro… |
| 3001 | DIAMETER_COMMAND_UNSUPPORTED The peer doesn't recognise or support this command code (DIAMETER_COMMAND_UNSUPPORTED) -- a protocol-level mismatch, not… |
| 3002 | DIAMETER_UNABLE_TO_DELIVER This isn't an answer from the home network -- it's a routing failure (DIAMETER_UNABLE_TO_DELIVER, RFC 6733). The node th… |
| 3003 | DIAMETER_REALM_NOT_SERVED The destination realm isn't served by the node that answered (DIAMETER_REALM_NOT_SERVED) -- the request was routed to a … |
| 3004 | DIAMETER_TOO_BUSY The peer is too busy to handle the request right now (DIAMETER_TOO_BUSY) -- a load problem on that node, not a rejection… |
| 3005 | DIAMETER_LOOP_DETECTED The request went round in circles between Diameter agents (DIAMETER_LOOP_DETECTED) -- a routing configuration loop. |
| 3006 | DIAMETER_REDIRECT_INDICATION The agent that answered is telling the sender to go directly to another host (DIAMETER_REDIRECT_INDICATION) -- normal be… |
| 3007 | DIAMETER_APPLICATION_UNSUPPORTED The peer doesn't support the Diameter application this request used (DIAMETER_APPLICATION_UNSUPPORTED) -- e.g. S6a isn't… |
| 3010 | DIAMETER_UNKNOWN_PEER The request came from a peer the receiving node doesn't know (DIAMETER_UNKNOWN_PEER). |
| 4001 | DIAMETER_AUTHENTICATION_REJECTED Authentication failed at Diameter level (DIAMETER_AUTHENTICATION_REJECTED). |
| 4010 | DIAMETER_END_USER_SERVICE_DENIED The charging server denied the service to this subscriber (DIAMETER_END_USER_SERVICE_DENIED). |
| 4012 | DIAMETER_CREDIT_LIMIT_REACHED The subscriber has no credit left (DIAMETER_CREDIT_LIMIT_REACHED) -- online charging refused more units. |
| 4181 | DIAMETER_AUTHENTICATION_DATA_UNAVAILABLE The HSS couldn't produce authentication vectors for this subscriber (DIAMETER_AUTHENTICATION_DATA_UNAVAILABLE, 3GPP TS 2… |
| 5001 | DIAMETER_AVP_UNSUPPORTED The peer received an AVP it doesn't support and that was marked mandatory (DIAMETER_AVP_UNSUPPORTED) -- an encoding/vers… |
| 5001 | DIAMETER_ERROR_USER_UNKNOWN The home HSS/HLR doesn't recognize the subscriber (DIAMETER_ERROR_USER_UNKNOWN) — the IMSI isn't provisioned on the home… |
| 5002 | DIAMETER_UNKNOWN_SESSION_ID The peer has no record of this Session-Id (DIAMETER_UNKNOWN_SESSION_ID) -- e.g. a CCR-Update for a session it already cl… |
| 5003 | DIAMETER_AUTHORIZATION_REJECTED Authorization rejected (DIAMETER_AUTHORIZATION_REJECTED). |
| 5004 | DIAMETER_ERROR_ROAMING_NOT_ALLOWED The home operator rejected roaming for this subscriber (DIAMETER_ERROR_ROAMING_NOT_ALLOWED) — almost always means there'… |
| 5004 | DIAMETER_INVALID_AVP_VALUE An AVP in the request carried a value the peer doesn't accept (DIAMETER_INVALID_AVP_VALUE) -- not a roaming decision. |
| 5005 | DIAMETER_MISSING_AVP A mandatory AVP was missing from the request (DIAMETER_MISSING_AVP). |
| 5006 | DIAMETER_RESOURCES_EXCEEDED The request exceeded a resource limit on the peer (DIAMETER_RESOURCES_EXCEEDED). |
| 5007 | DIAMETER_CONTRADICTING_AVPS The request contained AVPs that contradict each other (DIAMETER_CONTRADICTING_AVPS). |
| 5008 | DIAMETER_AVP_NOT_ALLOWED The request contained an AVP that isn't allowed in this command (DIAMETER_AVP_NOT_ALLOWED). |
| 5009 | DIAMETER_AVP_OCCURS_TOO_MANY_TIMES An AVP appeared more times than the command allows (DIAMETER_AVP_OCCURS_TOO_MANY_TIMES). |
| 5010 | DIAMETER_NO_COMMON_APPLICATION The responding node doesn't support the requested Diameter application (DIAMETER_NO_COMMON_APPLICATION). |
| 5011 | DIAMETER_UNSUPPORTED_VERSION The peer doesn't support this Diameter protocol version (DIAMETER_UNSUPPORTED_VERSION). |
| 5012 | DIAMETER_UNABLE_TO_COMPLY The remote node couldn't fulfill the request for a reason not covered by a more specific code (DIAMETER_UNABLE_TO_COMPLY… |
| 5030 | DIAMETER_USER_UNKNOWN The charging server doesn't know this subscriber (DIAMETER_USER_UNKNOWN, RFC 4006). |
| 5420 | DIAMETER_ERROR_UNKNOWN_EPS_SUBSCRIPTION The subscriber has no known EPS/LTE subscription (DIAMETER_ERROR_UNKNOWN_EPS_SUBSCRIPTION). |
| 5421 | DIAMETER_ERROR_RAT_NOT_ALLOWED This radio access type isn't allowed for this subscriber (DIAMETER_ERROR_RAT_NOT_ALLOWED). |
| 5422 | DIAMETER_ERROR_EQUIPMENT_UNKNOWN The HSS refused the request because the device is unknown in the equipment register (DIAMETER_ERROR_EQUIPMENT_UNKNOWN, 3… |
| 5423 | DIAMETER_ERROR_UNKNOWN_SERVING_NODE The HSS rejected a Notify from an MME/SGSN because it doesn't recognize that node as the one currently serving this subs… |
| 17 | Request accepted partially Request accepted, but only partially — some part of what was requested couldn't be fulfilled. |
| 18 | New PDN type due to network preference Accepted, but the network assigned a different PDN type than requested, based on its own preference. |
| 19 | New PDN type due to single address bearer only Accepted, but the network assigned a different PDN type because it only supports a single address bearer. |
| 64 | Context Not Found The responding node has no record of the context (session/bearer) this request refers to (Context Not Found) -- often me… |
| 65 | Invalid Message Format The request's message format itself was invalid (Invalid Message Format) -- a protocol encoding problem, not a policy re… |
| 66 | Version not supported by next peer The responding node doesn't support this GTPv2 version (Version not supported by next peer). |
| 67 | Invalid length An information element in the request had the wrong length (Invalid length). |
| 68 | Service not supported The responding node doesn't support the requested service (Service not supported). |
| 69 | Mandatory IE incorrect A required field in the request had an invalid value (Mandatory IE incorrect). |
| 70 | Mandatory IE missing A required field was missing from the request entirely (Mandatory IE missing). |
| 72 | System failure System failure on the responding side — not a policy rejection, an internal node error. |
| 73 | No resources available No resources available on the responding node. |
| 74 | Semantic error in the TFT operation The Traffic Flow Template in the request had a semantic error (Semantic error in the TFT operation). |
| 75 | Syntactic error in the TFT operation The Traffic Flow Template in the request had a syntax error (Syntactic error in the TFT operation). |
| 76 | Semantic errors in packet filter(s) One of the packet filters in the request had a semantic error. |
| 77 | Syntactic errors in packet filter(s) One of the packet filters in the request had a syntax error. |
| 78 | Missing or unknown APN The requested APN doesn't exist or isn't provisioned (Missing or unknown APN). |
| 80 | GRE key not found The GRE key referenced in the request wasn't found (GRE key not found) -- relevant to PMIPv6-based interfaces. |
| 81 | Relocation failure A handover/relocation procedure failed partway through (Relocation failure). |
| 82 | Denied in RAT The request was denied specifically for this radio access type (Denied in RAT). |
| 83 | Preferred PDN type not supported The requested PDN type isn't supported by the responding node (Preferred PDN type not supported). |
| 84 | All dynamic addresses are occupied No more dynamic addresses are available to assign (All dynamic addresses are occupied). |
| 85 | UE context without TFT already activated A context without a Traffic Flow Template was expected, but one is already active (UE context without TFT already activa… |
| 87 | UE not responding The UE never responded to a request the network sent it (UE not responding) -- the failure is on the radio/UE side, not … |
| 88 | UE refuses The UE explicitly refused the request (UE refuses). |
| 89 | Service denied The network explicitly denied this service (Service denied). |
| 90 | Unable to page UE The network was unable to page the UE (Unable to page UE) -- it couldn't be reached over the radio. |
| 91 | No memory available The responding node ran out of memory processing this request (No memory available) -- an internal resource issue, not a… |
| 92 | User authentication failed The subscriber failed authentication (User authentication failed) — almost always a credentials/security-key mismatch be… |
| 93 | APN access denied - no subscription Access denied — no subscription to this APN (APN access denied – no subscription). |
| 94 | Request rejected (reason not specified) The request was rejected without a more specific reason given (Request rejected, reason not specified). |
| 95 | P-TMSI Signature mismatch A P-TMSI signature mismatch was detected -- usually a stale/incorrect temporary identity being used. |
| 96 | IMSI/IMEI not known The responding node doesn't recognize this IMSI or IMEI at all (IMSI/IMEI not known). |
| 97 | Semantic error in the TAD operation A semantic error was found in the Traffic Aggregate Description of the request. |
| 98 | Syntactic error in the TAD operation A syntax error was found in the Traffic Aggregate Description of the request. |
| 100 | Remote peer not responding The node this request was sent to never answered at all -- the responding side of THIS message is reporting that a peer … |
| 101 | Collision with network initiated request This request collided with another request already in progress for the same subscriber/session (Collision with network i… |
| 102 | Unable to page UE due to Suspension The UE couldn't be paged because it's in a suspended state (Unable to page UE due to Suspension). |
| 103 | Conditional IE missing A conditionally-required field was missing from the request (Conditional IE missing). |
| 104 | APN Restriction type Incompatible with currently active PDN connection The requested APN Restriction type conflicts with a PDN connection already active for this subscriber. |
| 106 | Data forwarding not supported The responding node doesn't support data forwarding for this procedure (Data forwarding not supported). |
| 107 | Invalid reply from remote peer The response received from a further peer node was itself invalid (Invalid reply from remote peer). |
| 108 | Fallback to GTPv1 The responding node only supports GTPv1, not GTPv2, for this procedure (Fallback to GTPv1). |
| 109 | Invalid peer The peer that sent this request isn't a recognized/expected peer (Invalid peer). |
| 110 | Temporarily rejected due to handover/TAU/RAU procedure in progress The request was temporarily rejected because a handover/TAU/RAU procedure was already in progress for this subscriber --… |
| 111 | Modifications not limited to S1-U bearers The requested bearer modification wasn't limited to S1-U bearers as required for this procedure. |
| 113 | APN Congestion The responding node is congested for this specific APN (APN Congestion) -- a capacity/load issue. |
| 115 | UE already re-attached The UE has already re-attached, making this request obsolete (UE already re-attached). |
| 116 | Multiple PDN connections for a given APN not allowed This subscriber already has the maximum allowed PDN connections for this APN (Multiple PDN connections for a given APN n… |
| 117 | Target access restricted for the subscriber This subscriber is restricted from the access type/area being used for this request (Target access restricted for the su… |
| 119 | MME/SGSN refuses due to VPLMN Policy The MME/SGSN refused this request due to Visited-PLMN policy (MME/SGSN refuses due to VPLMN Policy) -- the visited netwo… |
| 120 | GTP-C Entity Congestion The responding GTP-C node itself is congested (GTP-C Entity Congestion) -- a capacity/load issue on that node, not a pol… |
| 121 | Late Overlapping Request This request arrived late, overlapping with a more recent one for the same subscriber (Late Overlapping Request) -- usua… |
| 122 | Timed out Request The request itself had already timed out by the time it was processed (Timed out Request). |
| 123 | UE is temporarily not reachable due to power saving The UE is temporarily unreachable because it's in a power-saving state -- not a fault, an expected radio-power-saving be… |
| 125 | UE not authorised by OCS or external AAA Server The UE wasn't authorized by the Online Charging System or an external AAA server for this request. |
| 126 | Multiple accesses to a PDN connection not allowed This subscriber already has another active access to this PDN connection, and multiple simultaneous accesses aren't allo… |
| 128 | S1-U Path Failure The S1-U user-plane path failed (S1-U Path Failure) -- a transport/bearer-plane issue, separate from the GTP-C control-p… |
| 129 | 5GC not allowed 5G Core access isn't allowed for this subscriber/request (5GC not allowed). |
| 130 | PGW mismatch with network slice subscribed by the UE The PGW doesn't match the network slice this subscriber is subscribed to. |
| 131 | Rejection due to paging restriction The request was rejected due to a paging restriction in effect for this subscriber. |
| 129 | New PDP type due to network preference Accepted, but the network assigned a different PDP type than requested, based on its own preference. |
| 130 | New PDP type due to single address bearer only Accepted, but the network assigned a different PDP type because it only supports a single address bearer. |
| 192 | Non-existent The responding node has no record of what this request refers to (Non-existent). |
| 193 | Invalid message format The request's message format itself was invalid (Invalid message format). |
| 194 | IMSI not known The responding node doesn't recognize this IMSI at all (IMSI not known). |
| 195 | MS is GPRS detached The subscriber is currently GPRS-detached (MS is GPRS detached) -- not attached to the packet-switched network at all ri… |
| 196 | MS is not GPRS responding The subscriber's device didn't respond (MS is not GPRS responding) -- the failure is on the radio/device side, not this … |
| 198 | Version not supported The responding node doesn't support this GTP version (Version not supported). |
| 199 | No resources available No resources available on the responding node (No resource available). |
| 200 | Service not supported The responding node doesn't support the requested service (Service not supported). |
| 201 | Mandatory IE incorrect A required field in the request had an invalid value (Mandatory IE incorrect). |
| 202 | Mandatory IE missing A required field was missing from the request entirely (Mandatory IE missing). |
| 204 | System failure System failure on the responding side — not a policy rejection, an internal node error. |
| 205 | Roaming restriction The subscriber is explicitly restricted from roaming here (Roaming restriction). |
| 206 | P-TMSI signature mismatch A P-TMSI signature mismatch was detected -- usually a stale/incorrect temporary identity being used. |
| 207 | GPRS connection suspended The subscriber's GPRS connection is currently suspended (e.g. during a 2G/3G voice call). |
| 208 | Authentication failure The responding node's own authentication procedure failed (Authentication failure) -- an internal issue on that side, di… |
| 209 | User authentication failed The subscriber failed authentication (User authentication failed) — almost always a credentials/security-key mismatch be… |
| 210 | Context not found The responding node has no record of the context this request refers to (Context not found). |
| 211 | All PDP dynamic addresses are occupied No more dynamic PDP addresses are available to assign (All PDP dynamic addresses are occupied). |
| 219 | Missing or unknown APN The requested APN doesn't exist or isn't provisioned (Missing or unknown APN). |
| 220 | Unknown PDP address or PDP type The responding node doesn't recognize the requested PDP address or PDP type (Unknown PDP address or PDP type). |
| 222 | APN access denied - no subscription Access denied — no subscription to this APN (APN access denied – no subscription). |
| 229 | APN Congestion The responding node is congested for this specific APN (APN Congestion) -- a capacity/load issue. |
| 1 | unknownSubscriber The queried network doesn't recognize this IMSI at all (unknownSubscriber) -- not "not reachable right now", but not pro… |
| 5 | unidentifiedSubscriber The subscriber couldn't be identified from the information given (unidentifiedSubscriber). |
| 6 | absentSubscriberSM The subscriber isn't reachable for a mobile-terminated short message specifically (absentSubscriberSM) -- the SMS equiva… |
| 7 | unknownEquipment The referenced equipment (IMEI) isn't recognized (unknownEquipment). |
| 8 | roamingNotAllowed The subscriber's home network explicitly disallowed roaming for this request (roamingNotAllowed). |
| 9 | illegalSubscriber The subscriber isn't allowed to use the network in the way this request implies (illegalSubscriber) -- typically an auth… |
| 10 | bearerServiceNotProvisioned The requested bearer service isn't provisioned for this subscriber (bearerServiceNotProvisioned). |
| 11 | teleserviceNotProvisioned The requested teleservice isn't provisioned for this subscriber (teleserviceNotProvisioned). |
| 12 | illegalEquipment The equipment (device) isn't allowed to use the network (illegalEquipment) -- e.g. blacklisted/barred IMEI. |
| 13 | callBarred Call barring is in effect for this subscriber (callBarred). |
| 15 | cug-Reject The call was rejected due to a Closed User Group restriction (cug-Reject). |
| 16 | illegalSS-Operation The requested supplementary-service operation isn't valid in this context (illegalSS-Operation). |
| 19 | ss-SubscriptionViolation The subscriber's subscription doesn't allow this supplementary service (ss-SubscriptionViolation). |
| 20 | ss-Incompatibility This supplementary service is incompatible with another one already active (ss-Incompatibility). |
| 21 | facilityNotSupported The requested supplementary service/facility isn't supported by the responding node (facilityNotSupported). |
| 22 | ongoingGroupCall A group call is already ongoing and conflicts with this request (ongoingGroupCall). |
| 25 | noHandoverNumberAvailable No handover number was available to complete the handover (noHandoverNumberAvailable) -- a resource/capacity issue on th… |
| 26 | subsequentHandoverFailure A handover that was already in progress failed partway through (subsequentHandoverFailure). |
| 27 | GMSC/gateway The response to a provideRoamingNumber request came back as absentSubscriber. This has two different real causes that lo… |
| 28 | incompatibleTerminal The subscriber's terminal is incompatible with what this procedure requires (incompatibleTerminal). |
| 29 | shortTermDenial A short-term restriction is currently denying this request (shortTermDenial) -- typically resolves on retry after a brie… |
| 30 | longTermDenial A long-term restriction is denying this request (longTermDenial) -- won't resolve on simple retry; something in the subs… |
| 31 | subscriberBusyForMT-SMS The subscriber was busy specifically for mobile-terminated SMS delivery (subscriberBusyForMT-SMS). |
| 32 | sm-DeliveryFailure The short message couldn't be delivered (sm-DeliveryFailure). |
| 33 | messageWaitingListFull The subscriber's message waiting list is full (messageWaitingListFull). |
| 34 | systemFailure An internal failure on the responding node (systemFailure) -- not a policy rejection. |
| 35 | dataMissing The request was missing a mandatory field the responding node needed (dataMissing). |
| 36 | unexpectedDataValue A field in the request had a value the responding node couldn't accept (unexpectedDataValue). |
| 39 | noRoamingNumberAvailable No roaming number was available to assign for this call (noRoamingNumberAvailable) -- a resource/capacity issue on the v… |
| 40 | tracingBufferFull The responding node's tracing buffer is full (tracingBufferFull) -- an internal operations/maintenance condition, not a … |
| 42 | targetCellOutsideGroupCallArea The target cell for a group call is outside the group call area (targetCellOutsideGroupCallArea). |
| 43 | numberOfPW-AttemptsViolation Too many incorrect password attempts were made (numberOfPW-AttemptsViolation). |
| 44 | numberChanged The subscriber's number has changed (numberChanged). |
| 47 | forwardingFailed Forwarding this call failed (forwardingFailed) -- distinct from a violation; the forward itself couldn't be carried out. |
| 49 | ati-NotAllowed Any Time Interrogation isn't allowed for this subscriber (ati-NotAllowed) -- a location-query request was refused by pol… |
| 50 | noGroupCallNumberAvailable No group call number was available to assign (noGroupCallNumberAvailable). |
| 51 | resourceLimitation The responding node is out of resources to handle this request (resourceLimitation) -- a capacity issue, not a policy re… |
| 52 | unauthorizedRequestingNetwork The requesting network isn't authorized to request this subscriber's location (unauthorizedRequestingNetwork). |
| 53 | unauthorizedLCSClient The requesting LCS client isn't authorized for this subscriber (unauthorizedLCSClient). |
| 54 | positionMethodFailure The positioning method itself failed (positionMethodFailure) -- a technical failure locating the device, not an authoriz… |
| 58 | unknownOrUnreachableLCSClient The requesting LCS client is unknown or unreachable (unknownOrUnreachableLCSClient). |
| 59 | mm-EventNotSupported The requested mobility-management event type isn't supported (mm-EventNotSupported). |
| 60 | atsi-NotAllowed Any Time Subscription Interrogation isn't allowed for this subscriber (atsi-NotAllowed). |
| 61 | atm-NotAllowed Any Time Modification isn't allowed for this subscriber (atm-NotAllowed). |
| 400 | Bad Request The request itself was malformed (Bad Request) -- a protocol/syntax issue, not a policy rejection. |
| 401 | Unauthorized Authentication is required and wasn't provided or was rejected (Unauthorized). |
| 403 | Forbidden The server understood the request but explicitly refused it (Forbidden) -- a policy rejection, not a technical failure. |
| 404 | Not Found The user/URI in the request doesn't exist at this server (Not Found). |
| 408 | Request Timeout The server gave up waiting for the request to complete (Request Timeout) -- the far end never responded in time. |
| 413 | Request Entity Too Large The request was too large for the server to process (Request Entity Too Large). |
| 416 | Unsupported URI Scheme The URI scheme in the request isn't supported (Unsupported URI Scheme). |
| 420 | Bad Extension The request used a SIP extension the server doesn't support (Bad Extension). |
| 421 | Extension Required The server requires a specific extension the request didn't include (Extension Required). |
| 423 | Interval Too Brief The requested registration/subscription interval was too short (Interval Too Brief). |
| 480 | Temporarily Unavailable The destination is temporarily unavailable (Temporarily Unavailable) -- e.g. not registered right now. |
| 481 | Call/Transaction Does Not Exist The call/transaction this request refers to doesn't exist on the server (Call/Transaction Does Not Exist) -- often a sta… |
| 482 | Loop Detected A signaling loop was detected (Loop Detected) -- a routing configuration issue. |
| 483 | Too Many Hops The request exceeded the maximum number of hops allowed (Too Many Hops) -- usually the symptom of a routing loop or misc… |
| 484 | Address Incomplete The dialed address/number was incomplete (Address Incomplete). |
| 485 | Ambiguous The destination address is ambiguous -- it matches more than one possible target (Ambiguous). |
| 486 | Busy Here The called party is busy (Busy Here) -- busy specifically at this endpoint, as opposed to everywhere (see 600). |
| 487 | Request Terminated The request was terminated before completing, usually because it was cancelled (Request Terminated). |
| 488 | Not Acceptable Here The destination can't accept the session as offered (Not Acceptable Here) -- typically a codec/media-capability mismatch… |
| 491 | Request Pending The request is pending behind another request already in progress for the same dialog (Request Pending). |
| 500 | Server Internal Error An internal error occurred on the responding server (Server Internal Error) -- not a policy rejection. |
| 501 | Not Implemented The responding server doesn't implement the functionality required to fulfill the request (Not Implemented). |
| 502 | Bad Gateway The responding server, acting as a gateway/proxy, got an invalid response from a further server it depends on (Bad Gatew… |
| 503 | Service Unavailable The responding server is temporarily unable to handle the request (Service Unavailable) -- usually overload or maintenan… |
| 504 | Server Time-out The responding server, acting as a gateway/proxy, timed out waiting on a further server it depends on (Server Time-out). |
| 505 | Version Not Supported The responding server doesn't support the SIP version used in the request (Version Not Supported). |
| 513 | Message Too Large The message was too large for the responding server to process (Message Too Large). |
| 600 | Busy Everywhere The called party is busy everywhere it could be reached, not just at this one endpoint (Busy Everywhere) -- distinct fro… |
| 604 | Does Not Exist Anywhere The destination doesn't exist anywhere on the network (Does Not Exist Anywhere). |
| 606 | Not Acceptable The destination exists but can't accept the session as offered anywhere it could be reached (Not Acceptable). |
| 1 | Unallocated (unassigned) number Unallocated number. |
| 2 | No route to specified transit network No route to the specified transit network -- a routing/configuration issue upstream of the destination, not the called p… |
| 3 | No route to destination No route to the destination at all -- a routing/configuration issue, not the called party being unreachable in the usual… |
| 6 | Channel unacceptable The channel selected for the call wasn't acceptable to the far end (Channel unacceptable). |
| 16 | Normal call clearing Normal call clearing — one of the parties hung up normally after the call was established. |
| 20 | Subscriber absent The subscriber is registered but currently absent (Subscriber absent) -- similar in spirit to a mobile-network absentSub… |
| 22 | Number changed The dialed number has changed (Number changed). |
| 26 | Non-selected user clearing The call was cleared by a party other than the one selected (Non-selected user clearing). |
| 27 | Destination out of order The destination is out of order (Destination out of order) -- an equipment/link failure at or near the called party. |
| 28 | Invalid number format (address incomplete) The dialed number's format was invalid or incomplete (Invalid number format). |
| 31 | Normal, unspecified Normal, unspecified — a normal call release without a more specific reason given. |
| 34 | No circuit/channel available No circuit/channel available — congestion on the call's route. |
| 38 | Network out of order Network out of order. |
| 41 | Temporary failure Temporary failure on the network side. |
| 42 | Switching equipment congestion Switching equipment congestion. |
| 44 | Requested circuit/channel not available The requested circuit/channel isn't available (Requested circuit/channel not available). |
| 47 | Resource unavailable, unspecified Resources unavailable, unspecified — a capacity/resource issue without a more specific cause. |
| 49 | Quality of service not available The requested quality of service isn't available (Quality of service unavailable). |
| 50 | Requested facility not subscribed The requested facility isn't subscribed to (Requested facility not subscribed). |
| 57 | Bearer capability not authorized The bearer capability requested isn't authorized for this subscriber (Bearer capability not authorized). |
| 58 | Bearer capability not presently available The requested bearer capability isn't currently available (Bearer capability not presently available) -- a capacity issu… |
| 65 | Bearer capability not implemented The requested bearer capability isn't implemented at all on the responding node (Bearer capability not implemented). |
| 69 | Requested facility not implemented The requested facility isn't implemented on the responding node (Requested facility not implemented). |
| 81 | Invalid call reference value The call reference value in the request was invalid (Invalid call reference value) -- a protocol/signaling issue, not a … |
| 88 | Incompatible destination The destination is incompatible with what was requested (Incompatible destination) -- e.g. a bearer/service mismatch. |
| 95 | Invalid message, unspecified The message itself was invalid, unspecified (Invalid message). |
| 96 | Mandatory information element is missing A field the protocol requires was missing from the message (Mandatory information element is missing). |
| 111 | Protocol error, unspecified A protocol error occurred, unspecified. |
| 127 | Interworking, unspecified An interworking issue occurred with another network/technology, unspecified. |
| 2 | IMSI unknown in HSS IMSI unknown in HSS: the home network doesn't have this subscriber for EPS (or for the CS part of a combined attach). |
| 3 | Illegal UE Illegal UE: the network considers the SIM invalid, typically after a failed authentication or a blacklisted identity. Th… |
| 5 | IMEI not accepted IMEI not accepted: the network refused the device's IMEI (used for emergency attach without a SIM, or EIR checks). |
| 6 | Illegal ME Illegal ME: the device (not the SIM) is blacklisted, e.g. by the EIR. |
| 7 | EPS services not allowed EPS services not allowed: the subscriber isn't allowed to use LTE/EPS at all. |
| 8 | EPS services and non-EPS services not allowed EPS services and non-EPS services not allowed: the subscriber can use neither LTE nor 2G/3G circuit services through thi… |
| 9 | UE identity cannot be derived by the network UE identity cannot be derived by the network: the MME couldn't map the GUTI the phone used to an IMSI (e.g. the old MME … |
| 10 | Implicitly detached Implicitly detached: the network had already detached the phone (e.g. after its timers expired). The phone has to attach… |
| 11 | PLMN not allowed PLMN not allowed: the subscriber may not use this network at all. The phone puts the PLMN on its forbidden list and won'… |
| 12 | Tracking area not allowed Tracking area not allowed: the subscriber may not use this tracking area (regional subscription). |
| 13 | Roaming not allowed in this tracking area Roaming not allowed in this tracking area: the subscriber can roam in this network but not in this area. |
| 14 | EPS services not allowed in this PLMN EPS services not allowed in this PLMN: LTE is not allowed for this subscriber in this network, but other networks or 2G/… |
| 15 | No suitable cells in tracking area No suitable cells in tracking area: the phone should look for another tracking area or network. Commonly used as a 'soft… |
| 16 | MSC temporarily not reachable MSC temporarily not reachable: the combined attach worked for LTE but the SGs/CS part failed for now. |
| 17 | Network failure Network failure: a failure inside the network not caused by the subscriber, e.g. the MME got no answer from the HSS. |
| 18 | CS domain not available CS domain not available: circuit-switched services (CSFB/SMS over SGs) aren't available; LTE data works. |
| 19 | ESM failure ESM failure: the attach failed because the bundled PDN connectivity request failed. The real reason is in the ESM cause … |
| 20 | MAC failure MAC failure: sent by the phone, not the network. The phone couldn't verify the network's authentication challenge: the v… |
| 21 | Synch failure Synch failure: sent by the phone. The SIM's sequence number (SQN) is out of sync with the HSS. Normally the network re-s… |
| 22 | Congestion Congestion: the MME is overloaded and asks the phone to back off (with a timer). |
| 23 | UE security capabilities mismatch UE security capabilities mismatch: the security capabilities echoed back by the network don't match what the phone sent. |
| 24 | Security mode rejected, unspecified Security mode rejected, unspecified: the phone rejected the Security Mode Command. |
| 25 | Not authorized for this CSG Not authorized for this CSG: the subscriber isn't allowed in this closed subscriber group (femtocell). |
| 26 | Non-EPS authentication unacceptable Non-EPS authentication unacceptable: sent by the phone when the authentication vector isn't an EPS one (e.g. AMF separat… |
| 39 | CS service temporarily not available CS service temporarily not available: CS fallback can't be served right now. |
| 40 | No EPS bearer context activated No EPS bearer context activated: the network has no active bearer for the phone (e.g. it lost the context). |
| 42 | Severe network failure Severe network failure: the network has a lasting problem and the phone should not retry for a while. |
| 8 | Operator Determined Barring Operator determined barring: the operator has barred this subscriber from the service. |
| 26 | Insufficient resources Insufficient resources: the network couldn't allocate resources for the PDN connection or bearer (often PGW/SGW capacity… |
| 27 | Missing or unknown APN Missing or unknown APN: the APN the phone asked for doesn't exist for it, or none was given and no default is subscribed… |
| 28 | Unknown PDN type Unknown PDN type: the requested PDN type (IPv4/IPv6/IPv4v6) isn't recognised. |
| 29 | User authentication failed User authentication failed: the PGW or an external AAA server rejected the user (PAP/CHAP, RADIUS) for this APN. |
| 30 | Request rejected by Serving GW or PDN GW Request rejected by Serving GW or PDN GW: the gateways refused the session; the GTPv2 cause in the Create Session Respon… |
| 31 | Request rejected, unspecified Request rejected, unspecified. |
| 32 | Service option not supported Service option not supported: the network doesn't support what was asked. |
| 33 | Requested service option not subscribed Requested service option not subscribed: the subscriber isn't subscribed to this APN or service (e.g. IMS APN not in the… |
| 34 | Service option temporarily out of order Service option temporarily out of order. |
| 35 | PTI already in use PTI already in use: the procedure transaction identity collides with one in progress. |
| 36 | Regular deactivation Regular deactivation: a normal release of the bearer or PDN connection, not an error. |
| 37 | EPS QoS not accepted EPS QoS not accepted: the phone or network rejected the proposed QoS. |
| 38 | Network failure Network failure: an internal network error prevented the session. |
| 39 | Reactivation requested Reactivation requested: the network asks the phone to re-establish the PDN connection (e.g. to move it to another gatewa… |
| 50 | PDN type IPv4 only allowed PDN type IPv4 only allowed: the phone asked for IPv6 or dual stack but only IPv4 is allowed for this APN. |
| 52 | Single address bearers only allowed Single address bearers only allowed: dual stack in one bearer isn't allowed; the phone may open a second PDN connection. |
| 53 | ESM information not received ESM information not received: the phone didn't send the ESM information (e.g. APN) the network asked for. |
| 54 | PDN connection does not exist PDN connection does not exist: the phone referred to a PDN connection the network doesn't have. |
| 66 | Requested APN not supported in current RAT and PLMN combination Requested APN not supported in current RAT and PLMN combination: e.g. the APN is not allowed over LTE in this visited ne… |
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