Inbound Calls Are Not Being Processed/Picked Up

[phattlmann]

I have an on-prem installation.
Version 20.0 Update 1 (Build 731 Release)

Did an upgrade to this over the weekend, and ever since there's been issues.
All inbound calls are failing. The caller hears ringing, however after 30 seconds it disconnects (which, is what is set at VOIP.MS).
In my call reports I see status as "unanswered" and the reason "Server error".
Previously I was seeing "unanswered" and the reason "Terminated by [caller]", whereas "caller" is the inbound calling party.

Completely at a loss as to what is going on, and after a lot of Googling, I can't find anything of relevance to help me.

 

[TheodorosG_3CX]

Does the call reach the PBX? Are you able to see it in the Active Calls?
If not then you need to clarify this with the provider first.