The responding node doesn't support this GTPv2 version (Version not supported by next peer).
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
Confirm both nodes support a common GTP version for this interface.
Check which node sent the response (MME, SGW or PGW): the cause belongs to that node's decision.
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