# File lib/openid/server.rb, line 1418
      def to_message
        namespace = @openid_message.get_openid_namespace()
        reply = Message.new(namespace)
        reply.set_arg(OPENID_NS, 'mode', 'error')
        reply.set_arg(OPENID_NS, 'error', self.to_s)

        if @contact
          reply.set_arg(OPENID_NS, 'contact', @contact.to_s)
        end

        if @reference
          reply.set_arg(OPENID_NS, 'reference', @reference.to_s)
        end

        return reply
      end