ok, now it's happening to me; again.
absolutely no hashing with one of my 14 card rigs. changed out SD cards and raspi. can login into admin page but no hashing. took rig apart and checked for any burnt boards (none) and blew out M board connector in case of excess oxidation (none apparent).
what were all the suggestions given for this frequent problem?
I've said it many times before, so I'll let you scroll up for details, but you need to check the output of chainminer and the proxies.