Nginx ssl port 433 not open/listening (refused to connect)

Question

I'm running nginx 1.6.2 on Linux and using CloudFlare origin certificates for HTTPS, I have installed the certificate and key in (for example) /path/to/certs and run chown 600 root on the directory and the certificate files (origin.pem and private.pem), when I try to open https://192.168.0.96 (on another computer) it says refused to connect. NMap shows port 80 is open, but not 443. Here is my /etc/nginx/sites-available/http file (www root is /var/www/http), modified according to the CloudFlare nginx config tutorial

server {
        listen 80 default_server;
        listen [::]:80 default_server;


        listen 443 ssl default_server;
        ssl on;
        ssl_certificate         /path/to/certs/origin.pem;
        ssl_certificate_key     /path/to/certs/private.pem;

        root /var/www/html;

        index index.html index.htm index.nginx-debian.html;

        access_log      /var/log/nginx.vhost.access.log
        error_log       /var/log/nginx.vhost.access.log
        server_name example.com

        location / {
                try_files $uri $uri/ =404;
        }
}

I'm happy to run additional diagnostics if that would help find the problem.