nginx as a reverse proxy on port 3000 fails

I have a domain (example.com), and have followed every step (I think I have atleast) of the nodjs tutorial on digitalocean (https://www.digitalocean.com/community/tutorials/how-to-set-up-a-node-js-application-for-production-on-ubuntu-20-04)

So, if I load up http://my_server_ip, I get the welcome to nginx screen.

If I load up my domain (example.com), the screen shows the sample html from the server nginx server blocks tutorial

If I load up my_server_ip:3000, nothing happens, even though localhost:3000 shows Hello World, from the node tutorial

My reverse proxy settings in the sites-available folder is as follows:

server {

        root /var/www/example.com/html;
        index index.html index.htm index.nginx-debian.html;

        server_name example.com www.example.com;

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

    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot


}
server {
    if ($host = www.example.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    if ($host = example.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


        listen 80;
        listen [::]:80;

        server_name example.com www.example.com;
    return 404; # managed by Certbot

}

server {

    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 check of the nginx files shows no errors, but I still cant see the hello world from outside the server. Can anyone point me in the right direction?