C.A.T.S.: Crash Arena Turbo Stars is currently available for iOS v.8.0+ and Android 4.1+. Stable Internet connection is required in order to play the game.
Make sure that you are connected to a steady Wi-Fi network. Keep in mind that if you are connected via mobile data (3G/4G) and the connection bars are full, it does not always guarantee a solid Internet connection. Networks can slow down or get overloaded at times, especially when you are playing in a moving vehicle or the network base station is too far away from your location.