Using ajenti as a subdomain on a web server

Have you tried this in your nginx-config? This helped me ... Just look at nginx reverse proxy with ajenti. This might help too.

server {

        listen 443;

        ...

        location / {
                proxy_pass https://127.0.0.1:8000;
                proxy_set_header  X-Real-IP  $remote_addr;
                proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
        }

        ...

}