I think you misunderstand our concepts. Our “private download links” are supposed to be accessible to anyone (both logged-in and non-logged-in users), while the “protected links” are accessible only to those whom you grant permission to.
I believe you should use our “protected links” instead of the “download links”.
It looks like you’re using a Nginx server or Apache with Nginx as a reverse proxy, which is not supported by our Free version.
Can you please drop us an email to hello(at)preventdirectaccess.com with a sample protected link so that we can double-check and advise you accordingly?