Fortnite is no stranger to various connectivity issues, but chances are that you're having trouble with User Auth Check Failed these days, in particular. We're not sure what triggers it, but the fix we've found seems just about finicky enough to work.
The catch with Fortnite User Auth Check Failed is that it, due to some combination of events, cannot authenticate your Epic account with the server. The fix you're about to read is an attempt at "unblocking" the service, and allowing your account to authenticate legitimately.
How to Fix Fortnite User Auth Check Failed?
According to the Reddit post we've come across, there are four steps you need to do to fix the problem. Note that this may require the PvE Fortnite: Save the World component of the game:
- Log out of the game and the Epic Store client completely. Turn off Epic Launcher and restart it from the bottom-up.
- Verify your Fortnite installation files via the Epic Store client.
- Turn on Fortnite, log into the game, and then log out immediately.
- Log into Fortnite: Save the World, then abandon any ongoing games you may have had.
According to the source, this should resolve the problem. However, you may not have access to Save the World, in which case there are a few things you could try out stil. For example, some people seem to have had luck with flushing their Windows DNS cache. Others have fixed the issue by resetting their Network Adapter.
Trying either (or both) of these is easy and fast, so we recommend you give the guides referenced above a shot if you just can't fix this problem. Good luck.
It might be worth keeping in mind that Fortnite and Epic are going through a rough patch, far as server stability goes. Even Borderlands 3's singleplayer mode was rendered unplayable a few days back.