A.3 Causes related to PLMN specific network failures and congestion/authentication failures
24.3013GPPNon-Access-Stratum (NAS) protocol for Evolved Packet System (EPS)Release 18Stage 3TS
Cause #16 – MSC temporarily not reachable
This EMM cause is sent to the UE if it requests a combined EPS attach or tracking area updating in a PLMN where the MSC is temporarily not reachable via the EPS part of the network.
Cause #17 – Network failure
This EMM cause is sent to the UE if the MME cannot service an UE generated request because of PLMN failures.
Cause #18 – CS domain not available
This EMM cause is sent to the UE if the MME cannot service an UE generated request because CS domain is not available and SMS in MME is not supported.
Cause #19 – ESM failure
This EMM cause is sent to the UE when there is a failure in the ESM message contained in the EMM message.
Cause #20 – MAC failure
This EMM cause is sent to the network if the USIM detects that the MAC in the AUTHENTICATION REQUEST message is not fresh (see 3GPP TS 33.401 [19]).
Cause #21 – Synch failure
This EMM cause is sent to the network if the USIM detects that the SQN in the AUTHENTICATION REQUEST message is out of range (see 3GPP TS 33.401 [19]).
Cause #22 – Congestion
This EMM cause is sent to the UE because of congestion in the network (e.g. no channel, facility busy/congested etc.).
Cause #23 – UE security capabilities mismatch
This EMM cause is sent to the network if the UE detects that the UE security capability does not match the one sent back by the network.
Cause #24 – Security mode rejected, unspecified
This EMM cause is sent to the network if the security mode command is rejected by the UE if the UE detects that the nonceUE does not match the one sent back by the network or for unspecified reasons.
Cause #26 – Non-EPS authentication unacceptable
This EMM cause is sent to the network in S1 mode if the "separation bit" in the AMF field of AUTN is set to 0 in the AUTHENTICATION REQUEST message (see 3GPP TS 33.401 [19]).
Cause #39 – CS service temporarily not available
This EMM cause is sent to the UE when the CS fallback or 1xCS fallback request cannot be served temporarily due to O&M reasons or a mobile terminating CS fallback call is aborted by the network during call establishment (see 3GPP TS 29.118 [16A]).
Cause #42 – Severe network failure
This EMM cause is sent to the UE when the network has determined that the requested procedure cannot be completed successfully due to network failure. The failure is not expected to be temporary and repeated request is not likely to succeed in near future.
Cause #78 –PLMN not allowed to operate at the present UE location
This EMM cause is sent to the UE to indicate that the PLMN is not allowed to operate at the present UE location.
NOTE: This cause is only used by the network towards UE in NB-S1 mode or WB-S1 mode accessing the network through a satellite E-UTRA cell.