P560 and Yealink T21E2 Phones. A lot of them in three different locations. From time to time, mentioned error occurs durring call.
Phones losts calls with this error code Q.850;cause=16. This is displayed on phone. There is BYE on P560. Nobody quits the calls manualy, of course. And for some time, this phone device cannot make another call. Nothing like this happens in same locations with different PBX.
We are trying to found problem with Yestar also, but it could be good to make this public, if someone is facing same problems. And this problem is big trouble for us. Because our customer makes 50k calls during one month.