HELP! where to look – why it "hangs up" the status!?

Help!
There is Asterisk (v.1.6.0), with developed trixbox (v2.8.0.4). There are about 40 SIP – subscribers. At one subscriber the channel or in “Hold” or “In Use” is sometimes suspended though at this moment he to anybody doesn’t talk. The Sip-client of Bria v at it. 2.5 . The same occurs if I put 3CX.
In the Active Channel (s) point this subscriber is fixed with a field
"192.168.7.32 5108 NDAxZmU1NTVmNmI 0x4 (ulaw) of No Rx: ACK"
, and in Sip Peers menu point:
“5108/5108 192.168.7.32 of D N A 27572 OK (105 ms)”
, and in Subscribe/Notify menu point:
“5108@ext-local: SIP/5108 State:InUse Watchers 12"
Help! ! ! where to look – why it “hangs up” the status! ?
Thanks!

I don’t have the answer to why, I can only suggest a possible solution. Obviously it’s an upgrade to a non-ancient version. Trixbox is a dead project, so a server upgrade is a good advice for many reasons.

This looks like a machine translation. I’ve read it several times and still cannot work out what it is trying to say. Could you please post a copy in the original language. Also try using very short sentences.

The CLI output shows no obvious problems.

As already noted, that version hasn’t been supported for several years, and Trixbox is not supported at all.

Friends, thanks for the help!
1 . Really the text I translate through a site “translate.ru”.
2 . Everything appeared simply: at the subscriber “5108” the last session was suspended. I learned it the “core show channels” team. There was “echo test” which suspend. Possibly, the subscriber in the client of Bria pressed two times repetition of the last dialed number (and it was - “echo test”, and then without having hanged up I began to call other subscriber. I had to make restart to service (“restart now”) and everything earned.
Thanks!