Please note that Royal Farm is an online game that requires constant and stable internet connection.
Please make sure that your device is connected to the internet. Try to switch between your networks (from Wi-Fi to mobile or vice versa) and try loading the game once more.
Also please make sure that there aren't any antiviruses or VPN-s that can block Royal Farm. Also,
For Android: if your progress was connected to Google Play/Facebook, try clearing Royal Farm app cache and data and then try to enter the game.
For iOS: if your progress was connected to Game Center/Apple ID/Facebook, try reinstalling the game.