IP ranger 18.104.22.168/24 can't resolver ptr record by google DNS.
ex: IP 22.214.171.124 have ptr record smtp-02.viettelidc.com.vn
if i check by command
dig -x 126.96.36.199 @188.8.131.52
dig -x 184.108.40.206 @ns.viettelidc.com.vn
i receive result ok. ip resolver to ptr record.
dig -x 220.127.116.11 @18.104.22.168
my ip can't resolver by google dns.
at this time, sometime i can resolver PTR from google DNS. sometime fail.