You might experience this problem due to a server maintenance. If this is the reason, you should be able to connect now. Being an online game (your data is stored on a server) in order to access the game, make sure that you are using a stable Internet connection. This might also cause the server error that you encountered. Also, try to clear cache of the application. To do this, go to the menu of your device > Settings > Applications > Manage applications > All, tap on Hay Day and select Clear Cache. After you did this, try to start the game. If the problem still persists, try to contact the developer for further assistance on the official website.