Translation:Please call me Maria.
DuoLingo usually seems to require either a form like "can i get" or "could you" or just the use of "please", but not a combination of the two. Call me Maria could be interpreted as a command (impolite) Could you call me Maria and Call me Maria please are more polite. I'd say the combination (e.g. Can i get a x please) is fine as well but just avoid this in the duolingo answers.