Won't play score

Hi, I made a score and I want to listen to it, so I know how it sounds. However, MuseScore doesn't want to play it. The play-button is grey and pressing the spacebar doesn't work either. I also don't hear a sound when I click on a note or write one. I tried restarting both MuseScora as well as my laptop, neither of that has worked. How can I fix that?

GIT commit: f51dc11