"Log in (Hold)" Error message on Xbox while playing Fortnite
This error message means that you may have two or more Microsoft/Xbox profile on the same console.
Follow these instructions to log in to your correct Xbox profile:
Press the Xbox logo in your control
Select the profile icon
Check if you've activated two or more Xbox profiles on your console
Close any secondary profile that you don't use to play Fortnite
Log in to your main Xbox profile to play Fortnite