Sip phone T21P Cannot configure sip server as %NULL%

[asenthil]

Thanks, The above solution works in that the phone does not register with SIP server.

On looking into the issue further, I have found that, when setting sip server parameters as %NULL% the phone unregisters and then immediately registers with the SIP server.

Is there any other way to overcome this unexpected behavior?

Expected outcome: When SIP server parameters are set to %NULL%, the change should be reflected in the UI, phone must unregister and NOT register again immediately.