Solution: Try having them send to either your Twitch ID, Rally ID or Rally Username, or Twitter username, depending on whether you signed up with Twitch, email, or Twitter, respectively. If one doesn't work, try one of the others. Note: The long alphanumeric RallyID should always work.
Cause: Site backend is a little picky. Databases are a scary place. For Twitch IDs specifically, Twitch Auth is a nightmare.