Phone will unregister after a change is made to DN (Cisco 9951 SIP Firmware)

[ebrowne_STS]

Hello,

I am a beginner in CUCM, and our company inherited a few clients that use it. I know how to add phones, add/update DNs, create translation patterns, etc..., but I've been having this issue. Whenever I make a change to a DN, the phone unregisters immediately. Rebooting the phone, or sending reset or restart from CUCM doesn't work. The only solution is to reload the system from CLI and then the phone would register fine. All phones in the system are using SIP firmware (how the previous person set it up).

What could possibly be the problem?

CUCM is version 11.5.1.11900-26

[Sadav Ansari · Accepted solution]

Delete all unassigned DN from Route Plan report then check. 

is auto registration enabled on your cluster ? If yes disable it then check.

[ebrowne_STS]

I did both things you mentioned, and was able to make a change to the DN and the phone stayed registered. Thank you.

[Sadav Ansari]

Cool