When Cisco IP phones in a CUCM Cluster have ITL or other security settings which are out of date, invalid, or mis-matched, this can cause a number of functional and operational issues such as:
- Phones are unable to de-register from one CUCM Cluster to another
- Phones are unable to download updated TFTP configuration file
- Phones are unable authenticate via HTTPS based Authentication URL
To recover from this situation, the ITL file on the phone can be deleted or erased via the phone’s administrative menu options. This process can be different depending on type of Cisco IP phone model and the firmware version it is running.
ITL File Delete/Security Settings Reset Process for Cisco 6921, 6941, 6945, and 6961 IP Phones
Based on App Load: SIP 220.127.116.11
Step 1) On the phone’s home/start screen, push the Applications button.
Step 2) From the Applications menu, select Admin Settings, which should be the 4th option.
Step 3) From the Admin Settings menu, select Reset Settings, which should be the 5th option.
Step 4) From the Reset Settings menu, select the Security Softkey, which should be the 4th Softkey option.
Step 5) Confirmation the reset by selecting the Reset Softkey, which should be the 2nd Softkey option.
The phone should then indicate that it’s resetting its security settings and will likely reset/reboot.