Which specific error comes up? Would you be able to fill in the blanks of the following? That will help dissect the problem. Thanks.
What Country/State/Province do you live in? Modem brand & model number: Router brand & model number: If Wireless, are you using a white or black external adapter, or an internal (Xbox 360S) adapter? Things you have tried: Is UPnP Enabled? Yes/no/Unknown Do you have a NAT error? If so, what is your NAT? Any Error Codes you encounter: Who is your ISP(Internet Service Provider)? After you run "Test Xbox LIVE connection" press “Y” for "More Info”. In the pop-up that appears, what are the following values, if shown? (If a value below does not appear for you, just leave it blank.)
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