How do I fix Epic game sign in failed?

How do I fix Epic game sign in failed?
Troubleshooting the Epic Games Launcher

Check the Epic Games server status.
Check for updates.
Verify system requirements.
Disable fullscreen optimization.
Clear the Epic Games Launcher’s webcache.
Run the Epic Games Launcher as an administrator.
Update graphics card drivers.
Reinstall the Epic Games Launcher.

Troubleshooting the Epic Games Launcher
  1. Check the Epic Games server status.
  2. Check for updates.
  3. Verify system requirements.
  4. Disable fullscreen optimization.
  5. Clear the Epic Games Launcher’s webcache.
  6. Run the Epic Games Launcher as an administrator.
  7. Update graphics card drivers.
  8. Reinstall the Epic Games Launcher.