Unable to add user acccount "there has been an issue with the information that you input"

I am attempting to add a new user to my Comcast business account, which is current and has mailboxes available (we are not over our email box limit).  I have attempted to add the user with his email address (no special characters; just his name), I have followed the password guidelines and received no errors but every time I click confirm I get the error message "there has been an issue with the information that you input. Please review and try again."  I have attempted to add this user from every browser possible, with different email address formats, different passwords that meet the guidelines but get that error message every single time.  Anyone run into this issue and have it resolved?