Error opening sound device


I very recently updated to MacOSMonterey v12.1 and am using Audacity 2.4.2.

As of today (Jan 28 2022) whenever I try to play back I get “Error opening sound device” notification. Normally this can be fixed by changing the project rate to 44,100 or one of the other rates. However, it is not working this time. Even aups that were running fine a couple of days ago won’t run. I have checked the Audio midi as recommended in the manual but can find nothing that looks amiss - it is recommending 44,100.

These things happen nearly always after an update. If anyone can help I would be very grateful. (BTW I’m not very computer literate so the simpler the explanation the better, thanks!)