Fortnite loading screen glitch fix for PS4, Xbox One, and Nintendo Switch Perform a hard reset of your console by holding the power button Turn the console back on and attempt to launch Fortnite If that doesn’t fix the issue, the next step is to delete and redownload the game

Running an application as administrator can give you administrative rights to use the app. And this will hopefully fix the Fortnite stuck on loading screen problem. Make sure Fortnite is closed. Right-click the Epic Games Launcher icon, and select Run as administrator. Click Yes if prompted by User Account Control for confirmation.

go into your xbox settings, system, manage storage devices,clear local saved games (this will delete saved content on the console which will be backed up with cloud saving) then clear but keep games and apps then just select your settings and sign back in hope this helps!