This problem seemed to happen recently but was likely causing issues before where the phone(s) do not ring.
Now there are a few reasons why this can happen especially if your adapter has DND mode enabled (disable it).
However that wasn't my issue and Ionly figured it out the other day when by fluke if you're on the phone (making a call) then calls will come in.
That's when Ifigured out the solution:
This likely app........