The Facebook API documentation doesn't clearly state if it's possible to read a secret or closed group feed that the user is a member of, and I didn't succeed no matter the permissions asked. It works with owned groups though (and the user_managed_groups permission).
Permissions
- Any valid access token for a public group (i.e. the group's privacy setting is OPEN).
- A user access token for a member of the group.
- The user_managed_groups permission can be used to read the group content for a group in which the user is an admin. This permission also allows the app to post as the user in the group if the app is also granted the publish_actions permission.
- An app access token can read posts it published in app and game groups that belong to it.
Does anybody succeeded reading a secret or closed Facebook group feed with the API?