Solution to random Let's Encrypt Certbot Connection refused / Invalid response Authorization Errors

Since I upgraded my Certbot from version 1.7.0 to 1.11.0, I was getting different errors with different domain names when executing certbot renew command.

When renewing

certbot renew --cert-name --dry-run

I get Invalid response AuthorizationError:

Using Let's Encrypt free SSL/TLS certificates with Nginx and achieve A+ rating in Qualys SSL Labs

The Let's Encrypt is a certificate authority that offers free and automated SSL/TLS certificates for your website(s). It issues certificates trusted by most browsers. In this article will show how to setup and automate the renewal of Let's Encrypt SSL/TLS certificates with Nginx.