Drobo 5N ( won't recognize login in Mac mini, Ok on pc.)

I got a mc mini because Im trying to transition from pc before Microsoft kills windows 7.
My problem is Drobo won’t recognize the login that I been using almost every week.
Has any body has had the same problem in the pass?
I tried to send a letter to Drobo support and the form tells me the info Im giving is wrong although Im getting it right from my Drobo.