Hey thanks for the report, couple of questions.
- Are you updated to the latest version of Fortnite? v13.20. You can make sure you are updated by visiting the App store on your device.
- What device are you on?
- Do you have another device or platform that you are able to login on?
- Have you tried these workarounds?
Workarounds
1) Reinstalling the game. If this does not work attempt workaround #2
2) Launch with the wifi and cell turned off, once you reach the no connection screen, then turn them back on and that might get you past the start up screen.