Unable to join party in Fortnite. Error code -91

Try the following troubleshooting steps to fix this issue:

1. Check the game server status to verify that there's no outage: https://status.epicgames.com/
2. If you're on PC, verify your game files: How do I verify game files in the Epic Games Launcher?
3. If you're on console, try clearing your cache:
   • How do I clear my PlayStation cache?
   • How do I clear my Xbox Series S|X cache?
   • How do I clear my Nintendo Switch cache?
4. For Playstation and Xbox users, make sure to enable crossplay when playing Fortnite: How do I turn Fortnite crossplay On or Off from my console?
5. Fix your Nat type on console:
   
   • PlayStation Connection Troubleshooting
   • Xbox Troubleshoot NAT errors and multiplayer game issues
   • Troubleshooting Issues Related to NAT
6. Restart your router or try to troubleshoot your connection: How to troubleshoot connection issues
7. Restart your device to refresh your system settings