Sampler stopped working

I'm on 3.7 and suddenly my sampler has stopped working even though it worked last week. I've downgraded to 3.6 and it still won't work. There is no audio coming through whatsoever (threshold is fine, etc). Does anyone have any idea what I can do?

Make sure inputs are set to "1 & 2"

Always reset the preferences after you change the OS. Did you do that?

I remember an old bug on the SAMPLER screen where the 'SAMPLE' button in the menubar was not active, it meant nothing happened when you hit ARM. Have you somehow managed to trigger this ancient bug?