I live in France and I’m a Free Mobile subscriber.
I have a Librem 5 phone with a BM818-T1 (and BM818-E1) modem to take advantage of the 700 MHz band.
Last October, I activated VoLTE. Receiving calls works perfectly.
However, when I try to make a call, it doesn’t go through. I have to reset the modem using the kill switch and initiate the call within 15 seconds of resetting the modem for the call to connect (sometimes I have to try several times).
This works, but it would be much more convenient not to have to reset the modem for every outgoing call.
When the call is initiated immediately after an incoming call ends, everything works fine. Could this be related to suspend mode?
Here are the firmware versions installed on my phone (Crimson).
I have the impression that this behavior is somewhat similar to what biketool described in adedicated topic.