You can most likely just disable the trunk, apply config, then reenable the trunk, apply config also. If that works it is mostly likely too long of a registration period.
Back when chan_pjsip was first released I had issues with VoIP.ms and stayed on chan_sip.
Eventually, I made it a point to switch everything to chan_pjsip and took the time to actually deal with this.
At the time VoIP.ms said, of course, “we do not support PJSIP.” Well we all know that means nothing because SIP is SIP. Our local channel driver doesn’t mean anything to our provider, assuming all the sip header and setting are sent the same.
After pushing, VoIP.ms pointed me to a wiki article that I can no longer find. But I posted about it on another community in June of 2017.
But basically, they said to reduce the expiration time from 3600 to 120.
Their current wiki article on the subject does not say anything about it.