Just hit **# on the keypad and the CIPCwill enable the button in settings for a factory reset. Sometimes the phone may run into issues or may be unable to register to another tftp server (eg. another CME or CUCM server) due to a bug or maybe due to the security settings tying it to a specific server.
Step 1 - Click Settings
Step 2 - Hit "**#"........
Video Links:
How To Setup 2 Phones on a Single CME Router and get the GUI going.
How to use Dialpeers with CME with two routers
How to implement call restrictions using COR / Class of Restriction
Getting started, let's enable ephones and DNs we can add a phone with........