Facebook changes there the API connection method. After having a security issue on Facebook Developer platform and increase the security of their developer platform and the sites that connect to it.

When you try to get the token for "pages_manage_instant_articles"

Invalid Scopes: pages_manage_instant_articles. This message is only shown to developers. Users of your app will ignore these permissions if present. Please read the documentation for valid permissions at https://developers.facebook.com/docs/facebook-login/permissions

 This error comes because of your app in Live mode.  To fix this Put your App in Development Mode.