PlayStation
Check that you have the right Fall Guys Launcher. Uninstall all versions of Fall Guys you have on your console, restart and then download again from your Game Library. (this is especially important if you have played the Beta.)
Switch
Sometimes logging in here https://www.epicgames.com/id/login by selecting Nintendo Switch as the login option will update your account and allow you to play.
All Consoles
Make sure your timezone is set to automatic (Synchronize Clock via Internet)
Xbox: https://support.xbox.com/en-GB/help/hardware-network/settings-updates/system-settings
PC
Try to verify your game files -
Epic Games - https://support.fallguys.com/hc/en-us/articles/6183395006098
Steam - https://help.steampowered.com/en/faqs/view/0C48-FCBD-DA71-93EB
Run your launcher as Admin (Right click, run as Admin)
C++
Failed to Login, please check your connection or Stuck on Loading/Connecting might mean an issue with C++.
You'll need to uninstall and reinstall it for Fall Guys to run.
Firstly we'll need to uninstall any existing Microsoft Visual C++ {year} Redistributable entries in Add/Remove Programs of Windows:
1. Uninstall from the Control Panel
In the search box on the taskbar, type Control Panel and select it from the results.
Select Programs > Programs and Features.
Press and hold (or right-click) on the Microsoft Visual C++ {year} and Uninstall + follow the directions on the screen. You will need to do this one at a time.
2. Restart Windows once completed.
3. Reinstall C++
Then, install the latest Visual C++ redistributable package from: https://docs.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170.
Install both https://aka.ms/vs/17/release/vc_redist.x86.exe and https://aka.ms/vs/17/release/vc_redist.x64.exe
You will get an error for one of them depending on your operating system - this is normal.
Finally, run Epic Games Store or Steam as Admin and start the game normally.
You can also try some standard updates for Windows:
Check for Missing or Corrupted System Files
This Windows tool helps to locate issues on your Operating System.
https://support.microsoft.com/en-us/topic/use-the-system-file-checker-tool-to-repair-missing-or-corrupted-system-files-79aa86cb-ca52-166a-92a3-966e85d4094e
Update Network Drivers
Network cards are something that rarely get updated so make sure they are the most recent version
Click Start > Device Manager
Expand the Network Adapters category, right click on each and Update Driver
You may need to visit the manufacturers website to get the most up to date driver
Further Steps:
The above is the usual resolution for this issue, if you still are stuck the issue is likely with your security or connection:
It could also be that the connection is failing due to SSL certificate issue, which means that your Windows Certificate Store is outdated and you can repair it by using the Windows Updater to download all available updates.