Issue with registering extensions

Hi guys,
We use three similar bases Yealink. Sometimes on one of them we have problems with accounts’ registering. We tried to connect base to other port on our switch and we tried to change this base to a new one two times(with same IP address). But we still have issues. Sometimes after restarting I can see on the base, that accounts are registered. On FreePBX these extensions unavailable, but I can receive calls to them and can’t to do outbound calls. These extensions usually don’t have same problems, when I try to use them in softphone. I can’t understand, what has happened. Maybe, issue is in our pbx

Try to debug SIP in Asterisk console while making outgoing calls. You can check if you receive the SIP INVITE message from IP Phone at all.