Account suspension

Sounds like you have more than one account on your console & one of the accounts has been suspended.

As using a secondary account to avoid a suspension on your main account is against the code of conduct then a console privilege suspension was issued to stop you from doing this.

The console suspension wont show on the enforcement site brandiesel linked but the account suspension will.You can appeal the account suspension if eligible,not the console suspension though.

Console suspensions are issued to stop people using a secondary account to avoid a suspension on their main account,which is against the code of conduct.

As mentioned,console suspensions can not be appealed & should end at the same time as the account suspension.

Sounds like a console privilege suspension.

Using a secondary account to avoid a suspension on another account is against the code of conduct so console privilege suspensions are issued to stop people from doing this.

One of the accounts on your console must be suspended & due to the console suspension all other accounts on that console will have the same restrictions as the suspended account but will work on other devices which is why your account works on your cousins
xbox.

The console suspension should end at the same time as the account suspension ends.

An account suspension completely blocks the affected account from being able to sign in to the Xbox Live service for the duration of the suspension. Account suspensions are issued for a specified duration, often of 1, 7, or 14 days, though egregious or repeated
violations can result in a permanent suspension.

Sounds like a console privilege suspension.

These are issued to prevent someone from using a secondary account to avoid a suspension on their main account which is against the code of conduct.

Your other accounts will work on other devices,not just your sons xbox while the suspension is in place.

Your son can appeal the account suspension if eligible via the link gds 1972 posted but console suspensions can not be appealed.