x870e Nova WiFi POST error 21

I have a faulty board I think. 95% of the time when starting it I get three long beeps (I had to add my own speaker) and code 21 on the panel. Renegotiating the RAM in the slots sometimes fixes it and then it runs flawlessly, but there's no guarantee it will boot again the next day, even if the device is unmoved.

Can I get confirmation from the board that code 21 is a memory addressibility issue before I RMA this? I assume it just has a defect I have the DIMM slots making the connection unreliable.

Hi everyone, third and hopefully last post here. I wasn't going to weigh in further but this result appears very close to the top when googling "x870e Nova WiFi" so I know people will be seeing it.

Code 21 ended up being bad RAM. It doesn't make sense that it would be bad RAM because booting in single-channel mode (eg, one stick in A2 or B2) worked fine, and rearranging the modules did nothing, and wiggling the RAM appeared to do the trick sometimes -- but it was the RAM.
Don't do what I did and RMA the motherboard, then the processor, and then the RAM -- if it's code 21, the RAM is guilty until proven innocent by another set of modules.

Remember - when trying a different module, don't be tempted to use whatever other modules you have lying around. The motherboard is only compatible with DDR5, not anything earlier.

Cheers from London.
newlander