"Fall Guys" has become free-to-play and has been released on additional platforms, meaning that a massive influx of new players and returning old ones will be joining the fun. However, as the number of players grows, so does the number of associated server issues preventing players from actually playing the game.
The "Fall Guys" Twitter account has posted about the problems players are having and has offered solutions to fix the more common issues, such as the frozen loading screen. If you encounter a "Failed to Login" error message, you should try logging in twice more first, just in case the game fixes itself.
If the problem persists, check the official "Fall Guys" Twitter account to see if the servers are down. If that isn’t the problem, check your internet connection, and if it’s fine too, "Fall Guys" is experiencing an issue they haven't addressed yet.