Facebook no longer allows posting to secret and closed groups if you are not an admin

Facebook removed an ability to make posts to secret and closed groups for non-admins of that group. Attempt to post to a secret group where you are not an admin will result an “Unsupported post request” or “The user has not authorized the application to perform this action” errors.

Plugin/API still can post to Facebook public groups if you just a member, but you you can post to secret and closed groups ONLY if you are an admin.

[Update] Facebook disabled its Groups API. Autoposting to any Groups is no longer possible with native Facebook API. Only NextScripts Premium API can post to Facebook groups now. NextScripts API for Facebook