Cause Dictionary (Cause)¶

A dictionary for looking up the failure reason codes (Cause) that appear in 5GC procedures by their meaning, occurrence context, and remediation direction. It collects representative examples rather than an exhaustive list.

5GMM cause (representative examples)¶

Source: TS 24.501 Clause 9.11.3.2 (5GMM cause)

Cause type	Value/Name	Meaning	Main occurrence context	Remediation direction	Spec
5GMM cause	#3 Illegal UE	UE is illegal (authentication not possible, subscription inconsistency, etc.)	Registration Reject	Check subscription/authentication information	TS 24.501 Clause 9.11.3.2
5GMM cause	#6 Illegal ME	ME (device) is illegal	Registration Reject	Check the device (IMEI, etc.)	TS 24.501 Clause 9.11.3.2
5GMM cause	#7 5GS services not allowed	5GS services not permitted	Registration Reject	Check the subscription contract/permission settings	TS 24.501 Clause 9.11.3.2
5GMM cause	#9 UE identity cannot be derived	The UE identifier cannot be derived	Registration Reject	Check the identifier (SUCI, etc.)	TS 24.501 Clause 9.11.3.2
5GMM cause	#11 PLMN not allowed	The PLMN in question is not permitted	Registration Reject	Check PLMN selection/roaming settings	TS 24.501 Clause 9.11.3.2
5GMM cause	#22 Congestion	Congestion	Reject (with back-off)	Retry after the back-off timer expires	TS 24.501 Clause 9.11.3.2
5GMM cause	#73 Serving network not authorized	Serving network not authorized	Registration Reject	Check authorization/SEPP/roaming settings	TS 24.501 Clause 9.11.3.2

NGAP Cause (representative categories)¶

Source: TS 38.413 Clause 9.3.1.2 (Cause)

Cause type	Value/Name	Meaning	Main occurrence context	Remediation direction	Spec
NGAP Cause	Radio Network	Radio network origin	NGAP procedure failure/release	Check the RAN-side factors	TS 38.413 Clause 9.3.1.2
NGAP Cause	Transport	Transport origin	Same as above	Check the SCTP/IP path	TS 38.413 Clause 9.3.1.2
NGAP Cause	NAS	NAS origin	Same as above	Check the NAS procedure/cause coordination	TS 38.413 Clause 9.3.1.2
NGAP Cause	Protocol	Protocol origin	Same as above	Check message consistency/encoding	TS 38.413 Clause 9.3.1.2
NGAP Cause	Misc	Other	Same as above	Check individual factors	TS 38.413 Clause 9.3.1.2

Authentication failures (Authentication Failure)¶

Source: TS 24.501 Clause 8.2.4 (Authentication Failure)

Cause type	Value/Name	Meaning	Main occurrence context	Remediation direction	Spec
Auth failure	MAC failure	AUTN MAC verification failure	When sending Authentication Failure	Check network authentication information	TS 24.501 Clause 8.2.4
Auth failure	Synch failure	SQN synchronization failure	When sending Authentication Failure	Proceed to the AUTS resynchronization procedure	TS 24.501 Clause 8.2.4

On the accuracy of values

This dictionary provides representative examples rather than an exhaustive list. The values and names listed are based on the Specs above, but since there are many 5GMM causes, only some are included. Check values marked "to be confirmed" against the specification for your Release and version. For the complete list, refer to TS 24.501 Clause 9.11.3.2 / TS 38.413 Clause 9.3.1.2.