I don't have speakers so I use earphones when I play the game.
If you start the game by pressing "play" on the patch checker screen, but don't have your earphones connected and connect them afterwards the sound doesn't work.
I've figured out that if you close the game and open it again with the earphone plugged in the sound works again just fine, so this problem isn't really life threatening (get it? threatening).
Anyways, it might not even be able to be fixed but just wanted to mention it.
threatening).