Make sure your game has the latest version. 
 
Please see the steps on how to get the latest game updates from the links below:
 
Windows 10 PC/Laptop: http://zynga.my/1SNChxW
 
In case you're still getting the offline error message, please try the following steps below:
 
Windows 10 PC/Laptop: http://zynga.my/1SNChxW