I am new to LetsEncrypt, but I think I have a pretty solid handle on how it works. I can get everything working just fine with the manual authenticator. But when I try to do the Apache, Webroot, or Standalone methods, I get the following error:
Client with the currently selected authenticator does not support any combination of challenges that will satisfy the CA. You may need to use an authenticator plugin that can do challenges over DNS.
I am on Ubuntu 16.04 using certbot 0.26.1 on an Azure Linux vm.