The request was denied specifically for this radio access type (Denied in RAT).
Where you see it
In the Cause IE of a GTPv2-C response (Create Session, Modify Bearer, Delete Session…) on S11, S5 or S8.
What to check
Check whether this subscriber/APN combination is allowed on the RAT (2G/3G/4G/5G) being used.
Check which node sent the response (MME, SGW or PGW): the cause belongs to that node's decision.
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