drupal facebook autopost working but post are not visible to public
You need to take your app out of development mode and make it live to the public. All of your previous posts will then appear to their appropriate audiences (and so will future posts).

You can do this by going to https://developers.facebook.com, going to your app's dashboard, then to App Review. At the top there is a Yes/No field for "Make app public?" Set it to yes.