Source note · Troubleshooting Cisco IP phone registration
Phones power cycle or reset because of a TCP failure while connecting to Unified CM or a failure to receive acknowledgements to their KeepAlive messages.
Checked 2026-09-24
- Vendor
- Cisco
- Product
- Unified Communications Manager
- Subsystem
- phone resets
- Deployment
- on-premises
- Region
- not restricted
- Release range
- 12.5(1)
- Checked
- 2026-09-24
Sources
- Troubleshooting Guide for Cisco Unified Communications Manager Release 12.5(1) — Device Issues — Cisco Systems, Inc. (www.cisco.com) · tier 2 current vendor documentation · Device Issues > Phone Issues > Phone Resets
Cite this note
APA
WarmTransfer. (2026, September 24). Troubleshooting Cisco IP phone registration: source note cisco-phone-registration-troubleshooting-resets-tcp. WarmTransfer. https://warmtransfer.net/knowledge/claims/cisco-phone-registration-troubleshooting-resets-tcp
BibTeX
@misc{warmtransfer-claim-cisco-phone-registration-troubleshooting-resets-tcp,
title = {Troubleshooting Cisco IP phone registration: source note cisco-phone-registration-troubleshooting-resets-tcp},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cisco-phone-registration-troubleshooting-resets-tcp},
note = {Source note cisco-phone-registration-troubleshooting-resets-tcp, checked 2026-09-24}
}