dns_responder: Return an error if failed to build a resource record am: a7f9e985e7

                    .rclass = ns_class::ns_c_in,

                    .ttl = 5,  // seconds

            };

            fillAnswerRdata(it->second, record);

            if (!fillAnswerRdata(it->second, record)) return false;

            answers->push_back(std::move(record));

            if (rtype != ns_type::ns_t_cname) break;

            rname = it->second;