Please try the following:

1.) Restart your router

2.) Restart your device

3.) If you're using mobile data, please try a strong and stable WiFi connection instead

4.) Try a different location with different WiFi

5.) Check if you have any VPN/PiHoles active on your network that could be blocking the game

6.) Contact your internet service provider to check your connection

If this does not work, please repeat the steps. If the problem persists, please contact support stating "Error Code 800."