Deploying phoenix with Nginx

Hello,
I am on my way deploying a phoenix app in a remote droplet by DO. Using a nginx server. So, I have created my server, all working, but on port :4000 (obviously). I am trying to forwards this port to my domain example.com, but something isnt right for sure. Viewed this post Need help with Nginx configuration, to serve phoenix app, but frankly idk what more to do.

My /etc/nginx/sites-available/example.com

upstream phoenix {
  server 127.0.0.1:4000 max_fails=5 fail_timeout=60s;
}
server {
        server_name  iex.venus.home;
        listen 80;
        client_max_body_size 30M;
        location / {
                allow all;
                proxy_http_version 1.1;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header Host $http_host;
                proxy_set_header X-Cluster-Client-Ip $remote_addr;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection "upgrade";
                proxy_pass http://phoenix;
        }
}

And my phoenix app is located (if necessary) → /var/www/example.com/phoenix.

The way is that my application is visible on IP:4000, but I want it forwarded to example.com. Hope everything is clear.

Best Regards,
ykostov