mail.transpackgroup.com has no CNAME records.
Question and response
Question
dig mail.transpackgroup.com. NS
Answer
The response has no answer records.
Authority
transpackgroup.com. 1378 SOA clara.ns.cloudflare.com. dns.cloudflare.com. 2396206349 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0