If an installed app on the OnePlus smartphone no longer functions properly, it may help to clear the cache of the corresponding app.
This will delete services and temporary files that may have overlaid each other and therefore cause application-related malfunction.

Note: Clearing the app cache does not delete existing files, only the cache.

Android 10 | OxygenOS 10.0
Step 1:  Open the  Settings
Step 2:  Tap on  Apps & notifications
Step 3:  Tap on  See all apps
Step 4:  Choose an  app
Step 5:  Tap on  Storage & cache
Step 6:  Tap on  Clear cache
  1. Open the Settings
  2. Tap on Apps & notifications
  3. Tap on See all apps
  4. Choose an app
  5. Tap on Storage & cache
  6. Tap on Clear cache

OnePlus Instructions