Q:

Nginx | getpwnam("nginx") failed (2: No such file or directory)

I'm trying to launch a Docker container with the following Nginx.conf file, but I always get a getpwnam("nginx") failed (2: No such file or directory) error. 
I tried using user nobody; in the main context but that didn't work either. 
I even created an nginx user on my Synology to see if that made a difference. 
This error didn't happen until I started adding SSL certs. Not really sure what I'm doing wrong!
http {
    server {
        listen         8080;
        server_name    www.servername.com;
        return         301 https://$host$request_uri;
    }

    server {
        listen         8443 ssl default deferred;
        server_name    www.servername.com;

            ssl_certificate_key          /privkey.pem;
            ssl_certificate              /fullchain.pem;
            ssl_trusted_certificate      /fullchain.pem;

            # Improve HTTPS performance with session resumption
            ssl_session_cache shared:SSL:10m;
            ssl_session_timeout 5m;

            # Enable server-side protection against BEAST attacks
            ssl_prefer_server_ciphers on;
            ssl_ciphers ECDH+AESGCM:ECDH+AES256:ECDH+AES128:DH+3DES:!ADH:!AECDH:!MD5;

            # Disable SSLv3
            ssl_protocols TLSv1.1 TLSv1.2;

            # Diffie-Hellman parameter for DHE ciphersuites
            # $ sudo openssl dhparam -out /etc/ssl/certs/dhparam.pem 2048
              # ssl_dhparam /etc/ssl/certs/dhparam.pem;

            # Enable HSTS (https://developer.mozilla.org/en-US/docs/Security/HTTP_Strict_Transport_Security)
              add_header Strict-Transport-Security "max-age=63072000; includeSubdomains";

            # Enable OCSP stapling (http://blog.mozilla.org/security/2013/07/29/ocsp-stapling-in-firefox)
            ssl_stapling on;
            ssl_stapling_verify on;
            resolver 8.8.8.8 8.8.4.4 valid=300s;
            resolver_timeout 5s;

        location / {
            proxy_pass              http://192.168.1.4:38077;
            proxy_set_header        X-Real-IP           $remote_addr;
            proxy_set_header        Host                $host;
            proxy_set_header        X-Forwarded-For     $proxy_add_x_forwarded_for;
            proxy_set_header        X-Forwarded-Proto   $scheme;
            proxy_redirect off;
        }
    }
}

A:

Figured it out. After looking at the official Nginx docker image and their docker-compose script, the user "nginx" is written into the image itself.
Basically the container must have screwed up. Missing an nginx user that was embedded in the image is a serious issue so I just delete the container (and the image just to be sure), redownloaded the image, and launched it again with exactly the same parameters and it ran fine.
The issue I think was I changed the volumes I mounted on the image a lot when figuring out nginx and such and I must have messed up the internal .conf somehow. 

