Do not regenerate the CallManager and TVS certificates at the same time. If both change together, phones cannot download new files until the ITL is deleted manually on each phone.
Checked 2026-10-01
- Vendor
- Cisco
- Product
- Unified Communications Manager
- Subsystem
- Certificate management
- Deployment
- on-premises
- Region
- not restricted
- Release range
- 8.x to 11.5, or any release where the ITL is signed by the CallManager certificate
- Checked
- 2026-10-01
Sources
- Understand CUCM Security By Default and ITL Operation and Troubleshooting — Cisco Systems · tier 2 current vendor documentation · Regenerate certificates section
Cite this note
APA
WarmTransfer. (2026, October 1). Troubleshooting phone trust and ITL failures in Unified CM: source note cucm-itl-trust-troubleshooting-no-simultaneous-cm-tvs. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-itl-trust-troubleshooting-no-simultaneous-cm-tvs
BibTeX
@misc{warmtransfer-claim-cucm-itl-trust-troubleshooting-no-simultaneous-cm-tvs,
title = {Troubleshooting phone trust and ITL failures in Unified CM: source note cucm-itl-trust-troubleshooting-no-simultaneous-cm-tvs},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-itl-trust-troubleshooting-no-simultaneous-cm-tvs},
note = {Source note cucm-itl-trust-troubleshooting-no-simultaneous-cm-tvs, checked 2026-10-01}
}