Thanks for trying those steps, LuMc. Sorry to see your Wi-Fi Calling failed to work for you. I'd like you to test some other steps for me.
- Apps icon > Settings > Network & Internet > Mobile network > Advanced > Advanced Calling
- Oprime Wi-Fi Calling
- Oprime When Roaming
- Tap one of the following available options:
- Prefer Other Cellular Networks (Roaming changes may apply)
- Prefer Wi-Fi (please test both to see what happens) Tap Save (Power the phone off and on)