Anton Dobrev said:
This seems like a CORS-related issue as the web app is loaded over 'https' but is trying to load a resource over "http" and not over "https" which is being blocked by IE.
Thanks for the reply, Anton! It does seem that way, as there's nothing wrong with hitting the URL directly. With Chrome it just silently alerts you to mixed content. Firefox requires you to turn off blocking for the site. Is there a similar feature in IE? I've been searching but can't find a way to allow this.