Ip Address instead of Domain Name

Hi There

Wordpress Installation based on Nginx.

I recently set up my Dns records and my site has a strange behavior.

If you try to connect to the domain name: ggtest.it you go to the site but the browser shows the Ip Address instead of the domain name!

Here is my Nginx configuration

server { listen 80 default_server; listen [::]:80 default_server ipv6only=on;

    root /var/www/html;
    index index.php index.html index.htm;

    # Make site accessible from http://localhost/
    server_name ggtest.it www.ggtest.it;

    # Per aumentare la capacità di caricamento in wordpress
    client_max_body_size 32M;

    location = /xmlrpc.php {
    deny all;
             }

    location / {
            # First attempt to serve request as file, then
            # as directory, then fall back to displaying a 404.
            # try_files $uri $uri/ =404;
            try_files $uri $uri/ /index.php?q=$uri&$args;
            # Uncomment to enable naxsi on this location
            # include /etc/nginx/naxsi.rules
    }

Have you any idea about what this can be due to?

Have you any suggestion to sort the problem?

Thanks!