Minecraft dynmap nginx proxy error pages. We port our dynmap plugin through a proxy so we can secure it with https, and enable it as a folder extension instead of a random port or a root folder.

mc_dynmap_nginx_proxy.conf

# /etc/nginx/sites-enabled/ssl.conf or default.conf. Change and add your configuration accordingly
#
# With this nginx configuration, we can default to showing an error page if the proxy fails. Our setup is
# a little unique, in that our domain name (mc.ourdomain.com) forwards anything 404 related to a our main
# site for server information (www.ourdomain.com/servers/minecraft) the only reason to use the mc subdoamin
# is to join the server, and view the map (mc.ourdomain.com/map). This config might be simplified if we
# were redirecting all other traffic (ie, the location = for specific image files may not be needed)
#

server {    
    listen 443 ssl;
    server_name mc.ourdomain.com;
    root /var/www/html/mc.ourdomain.com;
    index index.php index.html;

    location ^~ /map/ {
        # This error page actually exists in the /map/ folder
        error_page 500 501 502 503 504 = /500.php;
        proxy_pass http://192.168.1.250:8123/;
    }
    # Since everything is redirected by default, we need to specifically map files that will be used for the error page
    location = /map/sad_creeper_S.png {
        root /var/www/html/mc.ourdomain.com/;
    }
    location = /500.php {
        # We have a default action for .php files, but when nginx serves error pages, it seems to be ignoring that location directive
        # I'll update the gist if I figure out a better config
        # "root" must be used here instead of "alias", despite what people might say online about how root should never be used...
        root /var/www/html/mc.ourdomain.com/map/;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass unix:/var/run/php/php7.2-fpm.sock;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    }
    
    # You don't have to redirect everything else like this. I've only included it for example since I mentioned this is our setup is working
    location / {
        return 301 http://www.ourdomain.com/servers/minecraft;
    }
    
    # Other configs go here
}