Had a Fairphone 4 for several years, all working fine for calls, data etc.
Today, phone has gone silent. First noticed because could not hear a phone call. Checked, also no sound from Timer, or from a BBC Sounds programme. Volume is turned up and not muted. Not aware of having changed anything else, or any other problems.
I’ve actually fixed it - just a hard switch off and on again - should have thought about that sooner! None the wiser as to the cause, but hopefully it won’t happen again.