OPPO Find N2 Flip
It's not possible to use Wi-Fi calling
Solution 3 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 the Side key.
Simultaneously, press and hold the upper part of the Volume key and keep them both pressed until your phone restarts.