Domain returns 502 bad gateway, why can I no longer connect

I don’t really have a back end. The server is being run with nginx and I am coding the website myself. I am not using wordpress or any other kind of external program I am trying to build this all on my own.

/etc/nginx/sites-available/defaut

First to help make the configuration less confusing we can change the default file to whats desplayed below.

server {
  listen 80 default_server;
  listen 443 default_server;
  
  server_name _;
  
  return 444;
}

This returns a 444 on both ports 80 and 443 with a no respnse and closes the connection. This happens for any traffic hitting the server that is not jchud.ninja - essentially a black hole.

From what I can see the issue is you have incomplete server blocks. As I do not know what you file name is I am just going to assume it is the following…

/etc/nginx/sites-available/jchud.ninja and we will work with the blog.* domain.

we first change

server_name _ blog.jchud.ninja;

to

server_name blog.jchud.ninja;

we romove…

root /var/www/blog.jchud.ninja/html;

index index.php index.html index.htm index.nginx-debian.html;

location ~ \.php$ {
    include snippets/fastcgi-php.conf;

    # With php7.0-cgi alon
    # With php7.0-fpm:
    fastcgi_pass unix:/run/php/php7.0-fpm.sock;
}

These directive are conflicting with what I am assuming is the desired destination. The server block should look like this now. \

server {
    listen 80;

    server_name blog.jchud.ninja;

    location / {
        proxy_pass http://localhost:8080;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
        try_files $uri $uri/ =404;
    }    
}

Note that the blog application present on port 8080 needs to be active - Also noted these settings are non-ssl configurations.

The biggest issue that I see is that your server blocks are incomplete and in some cases conflicting. A couple questions I have are what are your back ends - ie your website (wordpress?) and your blog(ghost?)?

@jasonjpeters

# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

# Default server configuration
#
server {
	# SSL configuration
	#
	# listen 443 ssl default_server;
	# listen [::]:443 ssl default_server;
	#
	# Note: You should disable gzip for SSL traffic.
	# See: https://bugs.debian.org/773332
	#
	# Read up on ssl_ciphers to ensure a secure configuration.
	# See: https://bugs.debian.org/765782
	#
	# Self signed certs generated by the ssl-cert package
	# Don't use them in a production server!
	#
	# include snippets/snakeoil.conf;

	root /var/www/html;

	# Add index.php to the list if you are using PHP
	index index.php index.html index.htm index.nginx-debian.html;

	server_name _  jchud.ninja www.jchud.ninja;

	location / {
	proxy_pass http://localhost:8080;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
		try_files $uri $uri/ =404;
	}

	# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
	#
	location ~ \.php$ {
		include snippets/fastcgi-php.conf;
	
		# With php7.0-cgi alon
		# With php7.0-fpm:
		fastcgi_pass unix:/run/php/php7.0-fpm.sock;
	}

	# deny access to .htaccess files, if Apache's document root
	# concurs with nginx's one
	#
	location ~ /\.ht {
		deny all;
	}
}


# Virtual Host configuration for example.com
#
# You can move that to a different file under sites-available/ and symlink that
# to sites-enabled/ to enable it.
#
#server {
#	listen 80;
#	listen [::]:80;
#
#	server_name example.com;
#
#	root /var/www/example.com;
#	index index.html;
#
#	location / {
#		try_files $uri $uri/ =404;
#	}
#}

server {

	# SSL configuration
	#
	# listen 443 ssl default_server;
	# listen [::]:443 ssl default_server;
	#
	# Note: You should disable gzip for SSL traffic.
	# See: https://bugs.debian.org/773332
	#
	# Read up on ssl_ciphers to ensure a secure configuration.
	# See: https://bugs.debian.org/765782
	#
	# Self signed certs generated by the ssl-cert package
	# Don't use them in a production server!
	#
	# include snippets/snakeoil.conf;

	root /var/www/html;

	# Add index.php to the list if you are using PHP
	index index.php index.html index.htm index.nginx-debian.html;
    server_name www.jchud.ninja jchud.ninja; # managed by Certbot


	location / {
		# First attempt to serve request as file, then
		# as directory, then fall back to displaying a 404.
		try_files $uri $uri/ =404;
	}

	# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
	#
	location ~ \.php$ {
		include snippets/fastcgi-php.conf;
	
		# With php7.0-cgi alon
		# With php7.0-fpm:
		fastcgi_pass unix:/run/php/php7.0-fpm.sock;
	}

	# deny access to .htaccess files, if Apache's document root
	# concurs with nginx's one
	#
	location ~ /\.ht {
		deny all;
	}


    ssl_certificate /etc/letsencrypt/live/jchud.ninja/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/jchud.ninja/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot



}
server {
    if ($host = www.jchud.ninja) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    if ($host = jchud.ninja) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


	listen 80 ;
	listen [::]:80 ;
    server_name www.jchud.ninja jchud.ninja;
    return 404; # managed by Certbot




}

code

That is my default website nginx config, and this next one is my subdomains.

 ##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

# Default server configuration
#
server {
	# SSL configuration
	#
	# listen 443 ssl default_server;
	# listen [::]:443 ssl default_server;
	#
	# Note: You should disable gzip for SSL traffic.
	# See: https://bugs.debian.org/773332
	#
	# Read up on ssl_ciphers to ensure a secure configuration.
	# See: https://bugs.debian.org/765782
	#
	# Self signed certs generated by the ssl-cert package
	# Don't use them in a production server!
	#
	# include snippets/snakeoil.conf;

	root /var/www/blog.jchud.ninja/html;

	# Add index.php to the list if you are using PHP
	index index.php index.html index.htm index.nginx-debian.html;

	server_name _  blog.jchud.ninja;

	location / {
	proxy_pass http://localhost:8080;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
		try_files $uri $uri/ =404;
	}

	# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
	#
	location ~ \.php$ {
		include snippets/fastcgi-php.conf;
	
		# With php7.0-cgi alon
		# With php7.0-fpm:
		fastcgi_pass unix:/run/php/php7.0-fpm.sock;
	}

	# deny access to .htaccess files, if Apache's document root
	# concurs with nginx's one
	#
	location ~ /\.ht {
		deny all;
	}
}


# Virtual Host configuration for example.com
#
# You can move that to a different file under sites-available/ and symlink that
# to sites-enabled/ to enable it.
#
#server {
#	listen 80;
#	listen [::]:80;
#
#	server_name example.com;
#
#	root /var/www/example.com;
#	index index.html;
#
#	location / {
#		try_files $uri $uri/ =404;
#	}
#}

server {

	# SSL configuration
	#
	# listen 443 ssl default_server;
	# listen [::]:443 ssl default_server;
	#
	# Note: You should disable gzip for SSL traffic.
	# See: https://bugs.debian.org/773332
	#
	# Read up on ssl_ciphers to ensure a secure configuration.
	# See: https://bugs.debian.org/765782
	#
	# Self signed certs generated by the ssl-cert package
	# Don't use them in a production server!
	#
	# include snippets/snakeoil.conf;

	root /var/www/html;

	# Add index.php to the list if you are using PHP
	index index.php index.html index.htm index.nginx-debian.html;
    server_name www.jchud.ninja jchud.ninja; # managed by Certbot


	location / {
		# First attempt to serve request as file, then
		# as directory, then fall back to displaying a 404.
		try_files $uri $uri/ =404;
	}

	# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
	#
	location ~ \.php$ {
		include snippets/fastcgi-php.conf;
	
		# With php7.0-cgi alon
		# With php7.0-fpm:
		fastcgi_pass unix:/run/php/php7.0-fpm.sock;
	}

	# deny access to .htaccess files, if Apache's document root
	# concurs with nginx's one
	#
	location ~ /\.ht {
		deny all;
	}


    ssl_certificate /etc/letsencrypt/live/jchud.ninja/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/jchud.ninja/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot



}
server {
    if ($host = www.jchud.ninja) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    if ($host = jchud.ninja) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


	listen 80 ;
	listen [::]:80 ;
    server_name www.jchud.ninja jchud.ninja;
    return 404; # managed by Certbot




}

Can you post your NGINX Config for your domain and sub-domain?