Please follow the below steps:
1. Go to Settings>Apps>See all apps>Find the app>Storage&cache>CLEAR STORAGE and CLEAR CACHE
2. Swipe up the home page and clear all applications and then try again.
3. Uninstall the application and install it again.
4. Back up the data and restore the phone to factory settings.
If the issue persists, contact the Nothing Support Team for further assistance.