Q:

Nginx overriding the default server

I am trying to serve a webpy application under Nginx on debian linux (RasPi).
I can successfully serve the webpy app if I use any port other than 80. But If I try to use port 80, it is not possible to hit my webpy app, I will always see instead the default "Welcome to Nginx" page.
I have tried everything I can think of the disable the default page and override it with my webpy app but nothing seems to work. I have deleted the default link, and file out of their respective directories. I have tried pointing directly to sites-enabled/webpy rather than sites-enabled/* in nginx.conf. Still result is always the same, if I hit http://[ip-address]/ I will see the welcome to nginx page.
I have tried several times nginx -s reload and stopping/starting everything. And rebooting the device.
How do I override this so that it is serving my webpy app on port 80?
nginx.conf
user www-data;
worker_processes 4;
pid /var/run/nginx.pid;

events {
        worker_connections 768;
        # multi_accept on;
}

http {

        ##
        # Basic Settings
        ##

        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 65;
        types_hash_max_size 2048;
        # server_tokens off;

        # server_names_hash_bucket_size 64;
        # server_name_in_redirect off;

        include /etc/nginx/mime.types;
        default_type application/octet-stream;

        ##
        # Logging Settings
        ##

        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;

        ##
        # Gzip Settings
        ##

        gzip on;
        gzip_disable "msie6";

        # gzip_vary on;
        # gzip_proxied any;
        # gzip_comp_level 6;
        # gzip_buffers 16 8k;
        # gzip_http_version 1.1;
        # gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;

        ##
        # nginx-naxsi config
        ##
        # Uncomment it if you installed nginx-naxsi
        ##

        #include /etc/nginx/naxsi_core.rules;

        ##
        # nginx-passenger config
        ##
        # Uncomment it if you installed nginx-passenger
        ##

        #passenger_root /usr;
        #passenger_ruby /usr/bin/ruby;

        ##
        # Virtual Host Configs
        ##

        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*; # I even tried pointing directly to webpy instead of *

}

#mail {
#       # See sample authentication script at:
#       # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
#       # auth_http localhost/auth.php;
#       # pop3_capabilities "TOP" "USER";
#       # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
#       server {
#               listen     localhost:110;
#               protocol   pop3;
#               proxy      on;
#       }
#
#       server {
#               listen     localhost:143;
#               protocol   imap;
#               proxy      on;
#       }
#}

As far as I can tell this should make any thing inside of sites-enabled/ get served
I have only 1 thing inside of sites-enabled/
$ ls -la
total 8
drwxr-xr-x 2 root root 4096 May 31 17:49 .
drwxr-xr-x 6 root root 4096 May 31 18:08 ..
lrwxrwxrwx 1 root root   32 May 31 17:49 webpy -> /etc/nginx/sites-available/webpy

which is a link to sites-available/webpy
# webpy server
server{
  listen 80; # if I set this to 8080 then I can hit the app on that port.

  location / {
        fastcgi_param REQUEST_METHOD $request_method;
        fastcgi_param QUERY_STRING $query_string;
        fastcgi_param CONTENT_TYPE $content_type;
        fastcgi_param CONTENT_LENGTH $content_length;
        fastcgi_param GATEWAY_INTERFACE CGI/1.1;
        fastcgi_param SERVER_SOFTWARE nginx/$nginx_version;
        fastcgi_param REMOTE_ADDR $remote_addr;
        fastcgi_param REMOTE_PORT $remote_port;
        fastcgi_param SERVER_ADDR $server_addr;
        fastcgi_param SERVER_PORT $server_port;
        fastcgi_param SERVER_NAME $server_name;
        fastcgi_param SERVER_PROTOCOL $server_protocol;
        fastcgi_param SCRIPT_FILENAME $fastcgi_script_name;
        fastcgi_param PATH_INFO $fastcgi_script_name;
        fastcgi_pass 127.0.0.1:9002;
  }

  location /static/ {
      root /path/to/www;
      if (-f $request_filename) {
         rewrite ^/static/(.*)$  /static/$1 break;
      }
  }
}

I don't have any other files, or links inside of sites-enabled/ or sites-avaialbe/ I removed the default ones from these folders.

A:

When you set
listen 8080;

run 
sudo netstat -tlnp | grep nginx

and see what ports nginx is listening on. It should not be listening on port 80 at this point.  If it is try
sudo grep -rnIw "80" /etc/nginx

If nginx is listening on port 80, there must be a declaration for it somewhere under /etc/nginx
As a sanity check, I would also stop the nginx server completely 
sudo service nginx stop

and see if some other server is serving the default nginx page.

