Error message

I am running a Mac 10.13 High Sierra with Audacity 2.3.2 downloaded. I have been recording pieces for voice-over work with no trouble. However I went back to the Mac today and pressed Record but got a banner with the message : ‘Error opening recording device. Error message 9986 Internal PortAudio error.’ I have my audio preferences set up right and I have not upgraded to Catalina. Anybody got any ideas ?
Would be very grateful for any help.

First thing to try is rebooting the computer.