Please follow the below steps:
1. Clear all background apps to ensure that the phone has enough memory.
2. Restart the phone and then enter the app, Make sure there is enough memory and try again.
3. Go to Settings>Apps>See all apps>Find the app>Storage&cache>CLEAR STORAGE and CLEAR CACHE
4. Check whether the phone and the application have the latest system or version - if not, try upgrading them.
If the issue persists, contact the Nothing Support Team for further assistance.