Guideline 2.5.1 - Performance - Software Requirements
Your app uses the "prefs:root=" non-public URL scheme, which is a private entity. The use of non-public APIs is not permitted on the App Store because it can lead to a poor user experience should these APIs change.
Next Steps
To resolve this issue, please revise your app to provide the associated functionality using public APIs or remove the functionality using the "prefs:root" or "App-Prefs:root" URL scheme.
If there are no alternatives for providing the functionality your app requires, you can file an enhancement request.