nginx reverse proxy redirecting to wrong domain

I’m using this tutorial https://www.digitalocean.com/community/articles/how-to-host-multiple-node-js-applications-on-a-single-vps-with-nginx-forever-and-crontab to setup a node site with nginx. It helps create a reverse proxy. this is what my nano /etc/nginx/conf.d/mydomain.com.conf looks like

server { listen 80;

server_name mydomain.com;

location / {
    proxy_pass http://localhost:3000;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection 'upgrade';
    proxy_set_header Host $host;
    proxy_cache_bypass $http_upgrade;
}

}

The problem is that when I visit my domain, it’s redirecting to another domain that I have setup on the same server. I setup that other domain (a static page) using the nginx virtual hosts tutorial here https://www.digitalocean.com/community/articles/how-to-configure-single-and-multiple-wordpress-site-settings-with-nginx

One difference I noticed is that the nginx reverse proxy tutorial doesn’t do any of this symlinking between sites available and sites enabled which the virtual hosts tutorial does sudo ln -s /etc/nginx/sites-available/demo /etc/nginx/sites-enabled/demo

Do I have to somehow enable this file?

/etc/nginx/conf.d/mydomain.com.conf