If it says "Nothing found" when you signup with your gamertag, it means your account is not updated yet.

To ensure it is updated, please go to the following website:

Xbox: https://www.xboxgamertag.com/search/gamertag

or

PlayStation: https://psnprofiles.com/?psnId=gamertag

Replace gamertag with your account gamertag or username.

If the problem persists. please contact us or visit the Support Center.