My Ubuntu 18.04 server is running nginx and apache2 using this guide

I have my site-specific nginx config file /etc/nginx/conf.d/my_domain.conf. Inside the file, I have:

server {
 root /srv/my_site_root/;
 server_name x.x.x.x;

In my browser when I access x.x.x.x, the site is served up correctly. When I access using my_domain the server responds using apache's default /var/www