SSL: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch

Problem

Trying to configure and use an nginx server that uses intermediate certifcates, you get the error about values mismatch and nginx does not start

Solution

It seems that this is a common mistake and it is mentioned here: https://nginx.org/en/docs/http/configuring_https_servers.html. In order to fix this you will need to change/reverse the original order that you have concatenated the chain, as in:

Using nginx to redirect to a different port

Problem

You have a docker container with an application running in a port different than port 80 (ie port 3000), and would like to access it without specifying the port, by using the domain name only.

Solution

Use the nginx proxy_pass as follows:

server {
  listen 80;

  server_name your_server_domain_name.com;
  location / {
    proxy_set_header  X-Real-IP $remote_addr;
    proxy_set_header  Host $http_host;
    proxy_pass        http://127.0.0.1:3000;
  }
}

curl: (7) Failed to connect to localhost port 80: Connection refused

Problem

You would like to access a host set up with nginx after adding your own vhost configuration file in /etc/nginx/conf.d/myfile.smth, but you get Connection refused.

Solution

Make sure that your nginx configuration file has the .conf extension as /etc/nginx/conf.d/myfile.conf.