getpwnam("www") failed in /etc/nginx/nginx.conf

I copied the nginx.conf sample onto my ubuntu 12.04 box (I don't know where to put the other conf files. I'm an nginx noob). When I try to start nginx I get the following error:

abe-lens-laptop@abe:/etc$ sudo service nginx start
Starting nginx: nginx: [emerg] getpwnam("www") failed in /etc/nginx/nginx.conf:1
nginx: configuration file /etc/nginx/nginx.conf test failed

What does this error mean? How can I fix it? I found this post but my user is already set to www www (if you see in the linked file) How do I change the NGINX user?

The user you specified in your configuration, www, doesn't exist. Either create the user, or choose a user that does exist.

Your other option (if you don't want to create a new user) is to replace the user field in nginx.conf with:

user nobody;

Create the www user. On Ubuntu this should be done using the following command and flags:

sudo adduser --system --no-create-home --shell /bin/false --group --disabled-login www

nginx version: nginx/1.13.9 built by gcc 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.9) built with OpenSSL 1.1.0g 2 Nov 2017

just use

user  nobody nogroup;