monster1.themailspec.com has no CNAME records.
Question and response
Question
dig monster1.themailspec.com. NS
Answer
The response has no answer records.
Authority
themailspec.com. 3389 SOA pns1.cloud.sg. dnsadmin.cloud.sg. 2026022806 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0