Wrong Game User Id. The number is located in between users and profile. If you protect your account with two-factor authentication enter the six-digit verification code and complete sign in.
Select settings after clicking on the gear icon. When your son is playing he should press the Xbox button on the controller to bring up the Guide menu. Choose how to sign in to your Epic Account.
The game wont even let me edit.
From the lobby open the main menu in the top left corner. If you want to change your Riot Games ID and username you can do so every 30 days for free but changing your ID can be a little tricky. Log in to your Connections in your Account Management page and click the Disconnect button next to the console you want to unlink. If the setting iTunes App Store shows the correct ID please describe the issue youre having in greater detail.
