Answer by kaiser for Proxy using nginx

You have an unused upstream named backend where you are pointing nothing at the moment. Straight from the Nginx upstream docs:

upstream backend {    server backend1.example.com      weight=5;    server backend2.example.com:8080 fail_timeout=5s slow_start=30s;    server backend3.example.com      resolve;    server backup1.example.com:8080  backup;    server backup2.example.com:8080  backup;}server {    location / {        proxy_pass http://backend;    }}

The port gets set in the upstream, not the proxy_pass directive.