IP phone says “registration rejected”

[gokul2790]

Hello,

I had a phone configured in CUCM and it is registered. Then I did factory reset on my phone and that was working well for a while. Now, my phone suddenly shows ''REGISTRATION REJECTED''. Also, I checked the DNs and all those stuffs and everything looks fine. Could someone tell me what could be the reason for this.

[islam.kamal]

Hi

Can you try the below , please?.

1- try to delete ITL certificate , may be this is a security issue . On physical phone , go to setting - scroll down - security -**# -erase and check.

2- If 1 not working , please if you use automatic registeration , try to register the phone manually.

3- If 1 and 2 not work , just go to CUCM serviceabilty and restart RIS data collector.

Thank you

please rate all useful information

[Joseph Martini]

Are you using security with your CUCM cluster?  If the phones are supposed to register securely meaning they have an authenticated or encrypted profile on them, the locally significant certificate (LSC) could have expired which would explain why it was working and all of a sudden stopped working.  You can check if you cluster is setup for security by checking the Entperise Parameter for Cluster Security Mode ( 1 = secure, 0 = non-secure).

If you are not using a secure setup, are you seeing this problem with SIP phones or SCCP phones?  SIP phones more often have this problem when the directory number in the TFTP configuration the phone has does not match what is configured on CUCM.  Another cause could be if the phone cannot resolve the names of the CUCM servers if you have a hostname under System > Server, so the phone will try and register to the TFTP server after failing to resolve/reach the CUCM servers.  If the phone's TFTP is not in the call manager group configured on the device pool the same rejected message will be seen because CUCM will only allow the device to register to a server that is in the call manager group set on the device pool of the phone.