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

Recently redeployed my server and ran into this error AGAIN!

1031#1031: *2 connect() failed (111: Connection refused) while connecting to upstream, client: 77.98.141.183, server: ww2.zone,

Server config:

server {
    listen 80;
    listen 127.0.01;	
    listen [::]:80 ipv6only=on;
    return 301 https://$host$request_uri;
}
# HTTPS — proxy all requests to the Node app
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:5000/;
        proxy_ssl_session_reuse off;
        proxy_set_header Host $http_host;
        proxy_cache_bypass $http_upgrade;
        proxy_redirect off;
    }
}

My node server listens on port 5000. I just used pm2 to restart the service and it takes it offline.

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