Dear Samsung Member,
Greetings from Samsung Customer Support!
Please perform the below mentioned steps to resolve the issue.
1. Steps to turn on/off wifi calling feature.
From home, swipe up to access Apps.
Tap Setting > Wi‑Fi Calling. – or – Pull down the status bar to display the quick settings menu and tap. Wi-Fi Calling.
Tap On/Off to turn Wi-Fi Calling on or off.
2. Check device in Safe Mode.
1. Press and hold the Power key, when Power off icon appears.
2. Press and hold the power off icon.
To exit safe mode just restart your device.
For further assistance, register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report/Ask questions).
Thank you for writing to Samsung.
Samsung Customer Support