The playback feature is broken.

I opened Musescore today to find that the playback function stopped working. It didn't matter how many times I closed and re-opened the app, it still couldn't play the piece. It didn't matter which score I opened, it still wouldn't work. I checked to see if the audio port was set right, but I couldn't sync the audio output, because the button to do so was greyed out. I have no idea as to why this is happening, nor how to fix it.