Play does nothing
S1 - Blocker
Since I have copied and saved the attached score (which is very simple and done in 3.0.2 is some minutes), press play, buttons become grey but musescore does (apparently) nothing.
Tested some another score, same result.
Plays just fine here
Did you lock the screen and unlock it again? If so it is a duplicate of #283772: Can't play after change speaker jack from loudspeaker to earpods.
Using MuseScore 2 was working fine, so I rebooted and after reboot play was working again => problem "solved"
Happen again with another score.
Luckily that wasn't a score converted to V3 yet, so opening in V2 has avoided to reboot again.
Just restarting MuseScore should do. Maybe even restarting just the audio subsystem via Preferences > I/O