Even checking in in the I/O settings where you could see any incoming signal from the interface I get no input signal.
I tried it with a Scarlett Solo 2nd Gen, UMC1820 and the internal audio device. Not even the internal mic works. Output works fine. Gain is turned up and the interfaces signal lamps do light up. Direct monitoring features on the interfaces work as well.
The interfaces work with other computers.
Have tried completely reinstalling Studio One (with deleting application support folders), even installed several older versions.
Restarted Studio One and the Mac Book.
Checked all interfaces in the system preferences of the mac book and they actually do monitor an input signal.
Mac Book is macOS Catalina 10.15.1
Studio One 4 Professional