From Apple
5. 1.1 LEGAL: PRIVACY - DATA COLLECTION AND STORAGE
Upon further review, we found that your app is not in compliance with the following guideline(s):
Legal - 5.1.1
We noticed that your app uses Facebook login for authentication purposes but does not include account-based features offered by that site.
In order to use Facebook for authentication, your app must include significant account-specific functionality from Facebook.
Next Steps
Please revise your app to implement your own authentication mechanism, or incorporate significant account-specific functionality from Facebook.
If your app does include additional account-specific features from Facebook, please provide us with details on where we can locate these features in your app.
We noticed that your app uses Facebook login for authentication purposes but does not include account-based features offered by that site.
In order to use Facebook for authentication, your app must include significant account-specific functionality from Facebook.
Please revise your app to implement your own authentication mechanism, or incorporate significant account-specific functionality from Facebook.
If your app does include additional account-specific features from Facebook, please provide us with details on where we can locate these features in your app.