Nginx protected folder

Hello,

Im trying to protect some pdf files with the built-in protected folder settings on a client website.

if I look at the .vhost file for the website I got following lines added:

Code:

        location /images/dokumentation/ {
                auth_basic "Members Only";
                auth_basic_user_file /var/www/clients/client103/web507/web/images/dokumentation/.htpasswd;

                location ~ \.php$ {
                    try_files /e62adce96fc6290952f4838f83eb7c63.htm @php;
                }
        }

If I access following url: domain.tld/images/dokumentation/ I get prompted for login, if I try access following:
domain.tld/images/dokumentation/somefile.pdf I get direct access without getting prompted for login.

Any hints how to make sure all files are protected by login?