For now, change your MusicBee language to English, and then go to:
help > view error log > post the entries that appear whenever you try to play a song.
Edit: is this your first time using MB or has this "cannot play any file" error suddenly started popping up?
If so, then it's probably related to the Windows update that's got a few users spooked here:
https://getmusicbee.com/forum/index.php?topic=40823.0