I can't create an account for my own domain

My domain name is isuruonline.me but I can’t create an account for it. When I try to create an account message popups “The domain name is not available for registration”. So how can I fix it?

The domain name is already attached to your account epiz_20791507. Any particular domain name can only be hosted on our system once, you can’t add it to multiple accounts at the same time.