It's important that you are connected to a reliable network and you ensure that your device is receiving a strong signal. Only relying on full wifi signal or mobile data coverage does not completely guarantee that the connection is solid. This is due to the reason that these networks can sometimes slow down and get overloaded. Please note that is particularly true if you are playing in a moving vehicle, on public transport (especially underground) or in an elevator, for example.
Even the best internet has frequent drops in the connection that usually go unnoticed and the game is designed to withstand these. If this continues, however, the game times out. When this is a persistent issue, we recommend trying to play on other networks to see how it affects gameplay. Another strong recommendation would be to play using wifi with a reliable internet service provider, or a good 3G/4G/5G connection.