    # File lib/chef/formatters/error_inspectors/registration_error_inspector.rb, line 22
            def add_explanation(error_description)
              case exception
              when Net::HTTPServerException, Net::HTTPFatalError
                humanize_http_exception(error_description)
              when Errno::ECONNREFUSED, Timeout::Error, Errno::ETIMEDOUT, SocketError
                error_description.section("Network Error:","There was a network error connecting to the Chef Server:\n\#{exception.message}\n")
                error_description.section("Relevant Config Settings:","chef_server_url  \"\#{server_url}\"\n\nIf your chef_server_url is correct, your network could be down.\n")
              when Chef::Exceptions::PrivateKeyMissing
                error_description.section("Private Key Not Found:","Your private key could not be loaded. If the key file exists, ensure that it is\nreadable by chef-client.\n")
                error_description.section("Relevant Config Settings:","validation_key \"\#{api_key}\"\n")
              else
                "#{exception.class.name}: #{exception.message}"
              end
            end