# 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