I am trying to create a new email id on my custom domain in Windows Live Admin center. Email id is *** Email address is removed for privacy ***, but I get an error "That account name is not allowed for use with this service".

Can anyone pls. look into this issue and assist me how to proceed further.  I have tried to create this email id using different alternates like *** Email address is removed for privacy ***, *** Email address is removed for privacy *** as well, but was unsuccessful and got the same message.  I was able to create other email ids on this Domain but only this one cannot be created.

Please help me.

Thanks & Regards