Please try the following:
1. View other apps or webpages to confirm if the network is working properly. Check if mobile data is turned on and if your data package has exceeded its limitat. Alternatively, use WiFi.
2. Exit the game, remove the background cache and then re-open the game. Find the game app in Settings> Apps> See all Apps. Go to Storage & Cache in the game settings to clear the cache.
3. Uninstall and reinstall the game.
If the issue persists, contact the Nothing Support Team for further assistance.