securemail.seppmaildemo.com has no CNAME records.
Question and response
Question
dig securemail.seppmaildemo.com. NS
Answer
The response has no answer records.
Authority
seppmaildemo.com. 2393 SOA ns.seppmail.cloud. hostmaster.seppmail.cloud. 2026030501 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0