Sip phone T21P Cannot configure sip server as %NULL%

[asenthil]

Hello Support Team,

When attempting to disable a registered Yealink T21P phone by providing a configuration file with parameters,
account.1.sip_server.1.address = %NULL%
account.1.sip_server.1.port = %NULL%

the phones' UI still displays previous Sip server details and the phone continues to register with the sip server.

I am able to edit the parameters, but not remove them.
Any help would be appreciated.
Thank you!

[CWR]

try this:
account.1.enable = 0

[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.