Synthesizer, mixer and playback controls grayed out

I have recently installed Musescore 3.4.2 on my 2012 MacBook Pro. The other day I noticed that I could not playback files, did not hear the notes I was adding and playback controls, synthesizer and mixer are grayed out.

I have browsed interned and forums but did not find a solution that helped me (tried all the regular adivses), so now I am hoping someone here will be able to help me out.

Alghough I am not sure I believe I was able to use these controls until I connected my Mac to a friend's midi device. I am using an M-AudioMidisport 2x2 to connect my keyboard to my laptop (extremely simple set-up), I think his was an Akai (no sure about the model). Could that have something to do with it?

I am adding a screenshot of Musescore I/O preferences. As you'll see I cannot chose any PortAudio settings. All dropdowns are empty.

What I am using:
Musescore OS: macOS 10.15, Arch.: x86_64,
MuseScore version (64-bit): 3.4.2.25137, revision: github-musescore-musescore-148e43

Thanks for helping me out!