In WIFI calling mode several incoming calls go directly to voice mail
As an AT&T customer (4 phones, home wifi, ATT TV) I have very poor or no cell coverage inside my house. After the AT&T Microcell stopped working and AT&T support could not solve the problem, AT&T setup wifi calling in all iphones (7;10;10R all with ios13.3.)
Majority (not all) of the incoming calls in any of the phones go directly to voice mail .
Most of the time (not all) when trying to make an outside call, get "call failed" and after a few attempts then the call goes out.
Less problems with txt message.
If i switch wifi off and then on, seems some improvement. Tried with airplane mode and didnt solve the problem. All settings reset already done. Also seems that when the iphone is in sleep mode for a while the situation is worst. No problem using internet browsing or any other phone app. Home wifi service is working well.
ATT support is involved for more than 90 days, contacted apple support several times, they even run a diagnostic in the 10R (at the store) and no one could still solve the problem.
The case number is still opened at ATT specialized support. They are still looking for a solution. Already spent hours and hours over the phone with AT&T support.
Any idea how to fix this?