Please check your network connection. You may have difficulty connecting the game due to your current network status.
We do not recommend connecting to free public Wi-Fi Hot Spots. Try connecting to a stable 3G, 4G, LTE or private Wi-Fi network before launching the game again.
Make sure that the game is not having a maintenance or update.
You may also try to check if there is any issue with the Google account linked to the game which may cause the connection issue.