connect() failed (111: Connection refused) while connecting to upstream

Hi all,

Followed this tutorial to get Let’s Encrypt working on my Nest.js/Node server.

Everything works - running sudo nginx -t returns:

nginx: the configuration file /etc/nginx/nginx.conf syntax is ok nginx: configuration file /etc/nginx/nginx.conf test is successful

However, accessing my domain gives me a 502 Bad Gateway error. Specifically (from /var/log/nginx):

15004#15004: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 77.98.141.183, server: ww2.zone, request: "GET / HTTP/2.0", upstream: "http://127.0.0.1:8000/", host: "ww2.zone"

Here is my /etc/nginx/sites-available file:

Default server configuration
server {
    listen 80;
    listen 127.0.01;	
    listen [::]:80 default_server ipv6only=on;
    return 301 https://$host$request_uri;
}
server {
    # Enable HTTP/2
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name ww2.zone;

    # Use the Let’s Encrypt certificates
    ssl_certificate /etc/letsencrypt/live/ww2.zone/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/ww2.zone/privkey.pem;

    # Include the SSL configuration from cipherli.st
    include snippets/ssl-params.conf;

    location / {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-NginX-Proxy true;
        proxy_pass http://localhost:8000/;
        proxy_ssl_session_reuse off;
        proxy_set_header Host $http_host;
        proxy_cache_bypass $http_upgrade;
        proxy_redirect off;
    }
}

And my server is within a git Repo within home/username.

The code to listen on the port is: await app.listen(process.env.PORT || 5000);

This used to be process.env.PORT || 80 but that would throw:

Error: listen EADDRINUSE: address already in use :::80

Any ideas? Pulling my hair out atm.