Handling Declined Authorization Permissions
When your users are authorizing your application some providers such as Facebook allow the user to be selective over which attributes they wish to share. By default, this selection is only made when the user is first authorizing the app. If your user chooses not to allow certain attributes which are required by your application(such as email) the user will not be able to access your application. Your user will need to be reprompted for permissions and grant the required attribute to be able to login.
How to Reprompt for Permissions
Alternatively it can be set with Auth0.js, with