I get that same error as you if I try connecting using a local database user name and password.
If I try and connect with Mac Auth ClearPass complains about the Password being empty which triggers the following error
MAC-AUTH: Password in request doesn't match username. Not attempting MAC authentication
I have tried populating the usename and password with the Mac address and no luck.
The error "Client does not support configured EAP methods" I get whether a Certificate is installed or not. I started with the self signed Aruba Cert then when we got our signed Cert now I am unable to install the Public Cert from GoDaddy into the printer, the printer gives an invalid format error. I have tried every format I can export. It Says PEM/base 64 which is what I have tried numerous. Not sure if there is a bit limit or encryption type limit.
If I change the VC to Mac Auth first I can get a valid Mac auth in ClearPass but 3 seconds later it gets a reject. I really dont want my VC set to Mac Auth first so I put it back.
Same Model of HP Printer have tried 3 different Firmwares currently using the same as you 20150410.
The 802.1X documentation on this printer is very limited.
Not sure if any info above is of any help I will be working on it all day tomorrow too if I figure it out I will post.
Tom