Media Keys Don't work in Music App

I'm running Big Sur 11.4 on a 2017 27" iMac. The media keys (f7, f8, f9) don't work at all, even when in the Music App. I've had this happen with older operating systems, but it was usually only after opening a browser and using Youtube. In this case the media keys don't work at all, ever, under any circumstances.

Help!