Extension stopped working: Trying to establish CSTA session to <sip:[email protected]:2364>??

[correlative]

Hello All,

We came in this morning and one of our extensions/phones is down for some reason. No one touched anything over the weekend and the other 5 extensions/phones are working properly.

The phone in questions is a Yealink T21P/E2. We are on a cloud hosted instance of 3CX so it is provisioning through direct SIP/STUN. It worked fine last week and we've never had a problem with this before.

There are 2 things that are extremely weird:

1. The Activity Log Keeps showing this: 09/09/2019 1:05:14 PM - Trying to establish CSTA session to <sip:[email protected]:2364>. It has never shown this before.
2. In the Phones list, this phone shows up twice.

I tried checking firewall and restarting all services, removing and re-adding the phone and restarting all services and still nothing.

Can someone please help me figure out what is going on?

 

[correlative]

anyone?

 

[David Fowler]

I am in the same situation as you are. Remote office with one phone that was working until this week. Remote cloud hosted server, with Yealinks connecting via STUN. The 17 phones in my office work fine, but the other line is duplicated in the phones list, no audio, and no ring from external calls, and takes a very long time to register. The same CSTA session message every 30 seconds. Yealink T48S with 66.84.0.35 on all T48S handsets. Factory reset and reprovisioning didn't help.