Board Thread:Questions and Answers/@comment-26042064-20160424073319/@comment-24659969-20160424073814

When you open the app, you will need to have internet connection. The game requires connecting to server now to sync the time with the game internal clock to calculate how much energy you should've regained. Suppose you do not have internet, you can let the app runs in background and make sure it is not auto-killed by task manager or such.