If playing on Wi-Fi or cellular data, ensure you have a strong connection. This will help you have the best playing experience.
If on Wi-Fi, go to your Wi-Fi settings on your device and toggle it off and on to reset connection. Launch the game to see if the game connection has improved.
If on cellular data, check the number of bars you are receiving from your cell service. If you have less than full bars, wait until you have better service to retest your game and connection.