Getting Permission Error

Hi – I get a Forbidden permission error when I try to access the module via lightbox. “You don’t have permission to access You don’t have permission to access /wp-content/uploads/articulate_uploads/1508-content-audit-fundamentals/ on this server.” How do I fix that? The folder has 755 permission.

https://wordpress.org/plugins/insert-or-embed-articulate-content-into-wordpress/