in GTPv2 cause code 64 has name CauseContextNotFound about go-gtp HOT 2 CLOSED

"Context Not Found" is used in the response message by a GTP entity when it receives a message for which it does not have context, e.g. TEID-C or EBI is not known. When "Context Not Found" is received at Bearer Context IE level, it means the bearer context is unknown in the peer. When "Context Not Found" is received at message level together with a known TEID-C in the GTPv2-C header in the response message, this indicates some bearer contexts are not known in the peer; the sender of the request message should further determine, based on the bearer context(s) included in the request message, that: 
-	if the default bearer is unknown, this means the PDN connection is not known in the peer; 
-	if one or more dedicated bearers are unknown, this means only those dedicated bearer contexts are not known in the peer.


"Context Not Found" may be used by the PGW in the Create Session Response message during the non-3GPP to 3GPP access handover procedures, if the request corresponds to the handover of a PDN connection which does not exist in the PGW.

"Context Not Found" may be used by the PGW in the Create Session Response message during the 3GPP to non-3GPP access handover procedures, if the request corresponds to the handover of a PDN connection which does not exist in the PGW.