public function trySRVRecord()
    {
        $srvhost = '_autodiscover._tcp.' . $this->tld;
        $lookup = dns_get_record($srvhost, DNS_SRV);
        if (sizeof($lookup) > 0) {
            $host = $lookup[0]['target'];
            $url = 'https://' . $host . self::AUTODISCOVER_PATH;
            if ($this->tryViaUrl($url)) {
                return self::AUTODISCOVERED_VIA_SRV_RECORD;
            }
        }

        return false;
    }