This post goes through the steps of fixing Letsencrypt with the issue “Client with the currently selected authenticator does not support any combination of challenges that will satisfy the CA.”.
This post describes how to set up a SSL certificate with Certbot on Apache and Fedora. The guide primarily follows the guide on the certbot website however adds some additional information for if auto configuration fails.
This blog post describes how to set up free SSL certificates on a Web Host Manager CPanel server. This requires root access to the server, if you don’t have access to this then you must ask your service provider to install it for you. What is Let’s Encrypt? Let’s Encrypt is in their own words