I have a pretty standard test nginx configuration file (/etc/nginx/sites-available/default) that was configured to serve a sample html document.

Here's the modified portion of the configuration file.

upstream auth{
server 127.0.0.1:3000;
}

server {
listen 80 default_server;

root /var/www/index.html;

# Make site accessible from http://localhost/
server_name _;

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

location /auth{
proxy_pass http://auth;
}
}

And yet, accessing my machine's IP address seems to return a 404. What's going on here?

I've ensured that the permissions of index.html ensure that the file is readable, so doesn't seem to be a permissions issue.