Cisco advises comparing the certificate serial number and subject seen in the packet capture with the certificates shown in OS Administration Certificate Management to confirm which certificate is in use.
Checked 2026-10-02
- Vendor
- Cisco
- Product
- Unified Communications Manager
- Subsystem
- SIP TLS
- Deployment
- on-premises
- Region
- not restricted
- Release range
- CUCM 9.1(2) and 10.5(2) per technote
- Checked
- 2026-10-02
Sources
- Configure SIP TLS Trunk on the Communications Manager with a CA Signed Certificate — Cisco Systems · tier 2 current vendor documentation · Verify
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting Unified CM SIP trunks that show No Service: source note cucm-sip-trunk-no-service-troubleshooting-tls-serial-compare. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-sip-trunk-no-service-troubleshooting-tls-serial-compare
BibTeX
@misc{warmtransfer-claim-cucm-sip-trunk-no-service-troubleshooting-tls-serial-compare,
title = {Troubleshooting Unified CM SIP trunks that show No Service: source note cucm-sip-trunk-no-service-troubleshooting-tls-serial-compare},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-sip-trunk-no-service-troubleshooting-tls-serial-compare},
note = {Source note cucm-sip-trunk-no-service-troubleshooting-tls-serial-compare, checked 2026-10-02}
}