I work in IT and received some VLSC licenses that have been associated with my email account for work which is NOT a live, hotmail, or MSN account -- it is under my company's domain: username<at>mycustomit.com

When I try to make an account I receive the error:
This email address is part of a reserved domain such as live.com, hotmail.com, or msn.com. Please enter a different email address.

It has done this in the past and I have just used a personal account to register the licenses but I want to avoid having to do that again.

Please advise.

Thank you!