Might help if you included the handle and email you applied with. Offhand, perhaps either that domain's admin@ address was already used to register an account, or your application was denied for a reason other than the email.
I dare you to make less sense.
Are you a newbie, or do you have access to newbies?
From the topic it sounds like you are trying "firstname.lastname@example.org" .. since that is not a valid e-mail address unless you own yourdomain.com, that e-mail address is automatically rejected, as for some reason people try to register with it with frightening regularity.