Source note · Troubleshooting Cisco IP phone registration
When the Unified CM cluster is in non-secure mode, the TFTP server answers the phone's CTL file request with 404 Not Found.
Checked 2026-09-24
If the cluster is in non-secure mode, the TFTP sends 404 Not Found to the request.
- Vendor
- Cisco
- Product
- Unified Communications Manager
- Subsystem
- TFTP
- Deployment
- on-premises
- Region
- not restricted
- Release range
- current as of 2026-09-24
- Checked
- 2026-09-24
Sources
- Troubleshoot IP Phone Unregistration Issues in CUCM — Cisco · tier 2 current vendor documentation · Troubleshoot IP Phone Unregistration Issues in CUCM > configuration file download sequence
Cite this note
APA
WarmTransfer. (2026, September 24). Troubleshooting Cisco IP phone registration: source note cisco-phone-registration-troubleshooting-ctl-404. WarmTransfer. https://warmtransfer.net/knowledge/claims/cisco-phone-registration-troubleshooting-ctl-404
BibTeX
@misc{warmtransfer-claim-cisco-phone-registration-troubleshooting-ctl-404,
title = {Troubleshooting Cisco IP phone registration: source note cisco-phone-registration-troubleshooting-ctl-404},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cisco-phone-registration-troubleshooting-ctl-404},
note = {Source note cisco-phone-registration-troubleshooting-ctl-404, checked 2026-09-24}
}