securemail.seppmaildev.com has no CNAME records.
Question and response
Question
dig securemail.seppmaildev.com. NS
Answer
The response has no answer records.
Authority
seppmaildev.com. 45 SOA ns1.itmnetx.com. do-not-reply.seppmaildev.com. 2025090100 43200 7200 1209600 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0