Due to desperation I’ve solved this but in a dirty way. Go to the plugin itself, that is, wp-content/plugins/facebook-page-publish/fpp_index.php – go to line 662 and comment out the line and add $permissions = array(); above it so that it looks like below:
$permissions = array();
//$permissions = array(‘offline_access’, ‘share_item’);
That should solve it assuming you already have the other permissions manage_pages and user_groups
