Since this varies greatly from person to person I would like to create this topic in order to make the devs figure things out easier.
Fill out the following:
Provider: TDC
Country: Denmark
Provisions:
( type in calling app: #*#4636#*# for getting the information )
VoLTE: Yes
Video Calling Provisioned: Yes
WiFi-Calling: Yes
What doesn't work:
VoLTE doesn't work, Wifi Calling works fine.
@Mattias_ASUS You can tell the devs to look for this topic to fix further VoLTE issues. Some cant use Wifi Calling, others have VoLTE enabled in settings but doesn't actually work on their phone.