How do I get gmail to add this email to my contacts list?

I am trying to add an email address to my contacts address book in gmail. The email has a "_", "-", and a " ' " (underscore, dash, and apostrophe). The address ends with @mcpsmd.org . Gmail refuses to add it, saying that I need to recheck the email address or enter in a correct email address. I have tried switching between old and new versions, but neither work.