5G Troubleshooting Reference
Structured 5G troubleshooting guides for SA and NSA issues across registration, PDU session setup, NGAP/NAS/RRC signaling, mobility, paging, QoS, VoNR, RF conditions, transport paths, and user-plane behavior.
Recently Added
New 5G troubleshooting guides that are useful entry points for common field and lab failures.
5G Initial Access Troubleshooting
Isolate failures in cell search, PBCH decode, SIB1 acquisition, suitability checks, camping, and pre-random-access gating.
TAI and Tracking Area Mismatch Troubleshooting
Troubleshoot TAC broadcast errors, tracking-area restrictions, roaming-area mismatch, and area-related registration reject causes.
AMF Selection and GUAMI Issues
Troubleshoot wrong AMF targeting, stale GUAMI or 5G-GUTI context, and broken AMF-selection hints across RRC and NGAP.
5G Registration Failure Troubleshooting
End-to-end guide for registration reject, incomplete registration, AMF selection issues, and first-access failures.
Initial Context Setup Failure Analysis
Diagnose failures during Initial Context Setup and isolate core, policy, or radio-side blockers.
PDU Session Establishment Failure
Diagnose failed session setup, 5GSM reject causes, policy gaps, and missing path creation.
Paging and Service Resume Troubleshooting
Diagnose idle-mode reachability and recovery issues from paging through service resume.
Quick Paths
Start with the visible symptom when you need the shortest path into the right 5G troubleshooting branch.
5G Issue Categories
Browse the main 5G troubleshooting branches by failure domain.
Registration and Access Failures
Troubleshoot 5G registration reject, cell access problems, RRC setup failures, and incomplete initial access procedures.
Security, Authentication, and Identity Issues
Troubleshoot authentication failure, security mode rejection, key mismatch, SUCI or SUPI handling, and identity context problems.
Protocol Troubleshooting Paths
Use these when the trace already points toward a specific signaling layer or transport protocol.
Featured Guides
High-value fault-isolation guides that cover the most common 5G failure patterns end to end.
5G Registration Failure Troubleshooting
A full fault-isolation guide for registration failure, reject causes, AMF selection, TAI handling, and access path analysis.
Registration Reject Cause Analysis
Map common 5GMM registration reject causes to likely RAN, subscription, mobility, and core-side root causes.
PDU Session Establishment Failure
Diagnose 5GSM session reject causes, DNN mismatch, slice issues, policy conflicts, and missing user-plane setup.
Initial Context Setup Failure Analysis
Troubleshoot NGAP Initial Context Setup failure and isolate whether the fault sits in NAS, policy, transport, or radio handling.
Paging and Service Resume Troubleshooting
Troubleshoot missed paging, no response, failed resume, and idle-to-connected recovery issues.
Registration and Access Failures
5G Initial Access Troubleshooting
Troubleshoot cell search, SSB and PBCH detection, SIB1 acquisition, suitable-cell logic, camping, and access gating before random access.
5G Registration Failure Troubleshooting
End-to-end guide for registration reject, incomplete registration, AMF selection issues, and first-access failures.
Registration Reject Cause Analysis
Decode registration reject causes and connect them to likely access, subscription, mobility, or security faults.
AMF Selection and GUAMI Issues
Troubleshoot AMF routing, GUAMI mismatch, AMF reselection, and registration failure caused by serving core selection.
TAI and Tracking Area Mismatch
Diagnose tracking area related registration failures, forbidden areas, and mobility context mismatch.
PDU Session and Connectivity Failures
Signaling and Procedure Failures
Paging and Idle Mode Issues
FAQ
Quick answers for the main 5G troubleshooting starting questions.
How do I start troubleshooting a 5G registration failure?
Start by separating access failure from core-side rejection. Check whether the UE reaches RRC setup, whether NAS Registration Request reaches the AMF, and whether the reject is access, mobility, security, or subscription related.
How do I separate RAN issues from core issues in 5G?
Use the signaling break point. If failure happens before stable NAS delivery, it is often radio or access related. If NGAP and NAS complete but session or policy fails later, inspect AMF, SMF, UPF, and transport behavior.
Which messages matter most for PDU session troubleshooting?
Start with NAS PDU Session Establishment Request and Accept/Reject, then correlate NGAP context procedures and user-plane setup such as GTP-U or PFCP when traffic still fails after successful signaling.