If you are having trouble registering your Avaya 9630 IP phone, you may have to reset the phone's IP address. This simple tutorial also may be useful if you change networks and need to re-register the 9630.
Make sure the phone's screen is set to the main menu. Hold down the "Mute" key for about 3 seconds.
You will be prompted to enter a password. Enter 27238# (CRAFT#), the default password for all 9630 phones. The password must be entered immediately after the prompt appears.
Select "Change Address" from the Local Administration Procedures menu that pops up after entering the password.
Select "Change IP Address." The new address will be displayed on the screen. You may now register the phone.
If the password CRAFT# (27238#) does not work, try simply entering #. The default password cannot be changed, but can be disabled entirely, leaving only the pound (#) key.