thank you. I could try another carrier… BUT there was this forward leaning post from fiacco: "It need install: https://source.puri.sm/Librem5/bm818-tools/-/jobs/390480/artifacts/download 11
after install execute: sudo usermod -a -G dialout purism then reboot, then will see an app on Home, in order to work it need the modem enabled with sim card.
in this forumn : VoLTE support progress
Potentially this may also help the Modem to be more flexible/responsive/adapatable??? i.e. “work” in these restrictive carrier environments.
That “fix” is supposedly very new, not “fully” tested out yet…I will watch and wait and hope.