Have you tried syncing the latest mobile operator settings or doing a soft reset?
Is your Lumia 635 unlocked or locked to a specific carrier?
Have you been able to modify the WiFI calling settings before?
Thanks!
It is locked to TMO
I'll try to load the latest carrier settings
No soft reset yet, but it is on my list of next steps
Never tried to disable wifi calling on WM10 as I never had issues until this latest build
It drops calls every single time, even in full wifi signal - previous build did not have this issue
Overall, this latest build is a horrible step back in performance on L635 512MB - everything has gotten extremely slow. 5-10 sec to launch or switch apps. News app and edge keep crashing non -stop. The previous build was snappy and stable.