I have an R440 4x3.5 bay server that has the latest bios 2.21.1 and I installed a Xeon Gold 6242 CPU that was listed as allowed from Dell's thermal restriction matrix at Dell R440 Thermal matrix

When I booted the server, I'm getting an UEFI0384 Unsupported processor.

That CPU is listed as having 150W TDP and is also on the approved list.  I'd rather not have to waste the $1000 we just spent on processor upgrade.