I am desperate for some assistance please. We took over a client quite some time ago and in the contract we said we would assist with their VOIP (this is not something we support in general). Basically, the PBX had been working fine untill their provider closed their doors and they ported to a new provider.
Basically, what happens is only on the inbound calls, the trunk randomly goes dead and says "waiting for authentication". There is no pattern to this, it could be 5 times in 1 day, or 1 time in 5 days. Initially when this happened I would disable / enable the trunk and it would come back up.
Something strange that I found totally by accident, is the connection will re establish if I simply open the IVR settings and click Save and apply ( no editing or anything is done at all but this brings the connection up again).
I have spoken to the ISP multiple times and they say it is not on their side. The client is getting very frustrated at this point and it is wasting alot of my time as well constantly having to watch the connection in an RDP session.
If anyone has any advice, PLEASE let me know if you can think of anything to try and resolve this. Thank you in advance.