error opening sound device and error opening recording device

I’m on an iMac using an OS 10.14.4 and Audacity 2.4.2

All of a sudden I can’t record or playback. When I try to record I get a message that says “error opening recording device Error code -9997 Invalid sample rate.” But I didn’t change the sampling rate. It is at 40100. So I tried changing it to 48000 since that’s used for DVD’d but I got the same message. Now It’s back at 40100 and I get the same message.

When I try to playback a track I get the message "Error opening sound device. Try changing the host, playback device and the project sample rate.

Yesterday I could both record and playback with no problems. Any ideas? I checked all the connections between my Focusrite Scarlett Solo interface and the computer and even changed the USB port connection between them. Same messages.

Do you have other audio software running?

What are you trying to record?

Have you tried rebooting the computer?