Well according to your IP address, your internet provider is www.att.net , using an email from them will always work. What also will work is a work email address, school email address, paid for private domain that starts with webmaster, admin or info. Or if you are in the military, a military email address is also acceptable.
What is not acceptable is anything free (hotmail, google, yahoo, zzn.com etc etc)
also, in the news section, one player that needs to be given XP's e-mail is gmail! and you don't have to pay for gmail(unless google has two diffrent email services) than either it exepted it or he/she is a mod or it's an alteranate email addrese