401 messages to a single extension on outgoing calls

Newer installation Asterisk 13.12.2 FPBX version 10.13.66-11 (Currently , as I write this undating to 10.13.66-17)
Small install 8 phones. One phone gets a call fail message on most outgoing calls. Does not appear to be related to local or long distance differences. I ran TCPdump on the system and I am getting a 401 from the phone system to the phone. Dialing the same numbers from different phones have no issues. I see no issues with the outgoing route, it is pretty basic. We are using sip trunks. Just in, calls to other phones are doing the same thing. Call fail. There have been random reports here of not being able to call between phones. But I haven’t seen it until now.I am going to default the phone and delete the extension and see how it goes. The phone is made by Escene BTW.
Any ideas greatly appreciated.