VoWiFi gone after phone reset

lucian

I had my phone taken to service (street shop, post warranty) for screen replacement. Before that I reset it to factory defaults so that the service guys can turn it on and check it freely.

Once I got it back I also received a software update with Google's security patch for October. All good.

The thing is that the VoWiFi feature that I had active and functional before the reset it is now both turned off and gone from the settings.

Why? How do I turn it on? Must it somehow be triggered/provisioned by the operator (Orange Romania)?