I am trying to sort my custom post type in a few different ways using a dropdown.
When I try to sort it as the display_name it doesn't work.
$wp_query = new WP_Query(array('orderby' => 'display_name') );
It works well on a few other sort ways like 'title' 'comment_count' but when I want to sort from the authors real name and not username it doesn't work anymore. Any hint how this can be fixed?