Hi.
My phone decides when to ring or not or change sounds or vibrate or not by its own.
If not a misbehavior of the operative system, I suspect my ear is rubbing some exciting parts in the settings and things change. How to superlock settings so I will always have ringing when receiving a call, or a message, or a whateversapp ?
The stupid 'do not disturb' and 'shortcut to prevent ringing' settings are a piece of sheet when they change by themselves. -or do not allow changing-

 

I thought my Samsung Android was doing the same thing, changing setting, didn't get call or text notifications. When I looked closer at the problem, it turns out I was the problem. When holding the phone during a call I was touching the volume control that works the ring and text volume.