Sony Xperia 10
It's not possible to use Wi-Fi calling
Solution 2 of 4: Your phone needs to be restarted
If your phone is slow or freezes, it might help to restart it.
If your phone is slow or freezes, it might help to restart it.
Press and hold On/Off.
Simultaneously press and hold the upper part of the Volume key and keep them both pressed until your phone restarts.