This error message usually occurs if you have recently reinstalled or transferred the app to a different device.

If you've already updated to the latest version available in the app store on the device where you are seeing this message, this may be expected. The reason this occurs is due to the way new updates are released to small amount of players at a time in order to make sure everything is working properly. 

This issue will correct itself within a few weeks when the update is released to all players. At that time, your device will receive the next update and you will be able to access your account once again. In the meantime, you should be able to continue playing on the other device where you had installed the latest update.