OPPO A57 has no sound when incoming calls but has sound when playing music. How to solve the problem?

Reason 1:

Click Settings on the desktop - Enter Information.

Then turn off message harassment prevention. If this function is turned on, messages from unknown numbers will be silent (this function may not be available on some models).

Reason 2:

Enter the notification and status bar by clicking Settings on the desktop.

Enter notification management--click on information.

Then turn on notification ringtone and vibration.

If relevant situations arise in the future, you can follow the above methods to see