mx.transmail.eu has no CNAME records.
Question and response
Question
dig mx.transmail.eu. NS
Answer
The response has no answer records.
Authority
transmail.eu. 300 SOA ns1.zohocorp.com. dnsadmin.vtitan.com. 2026022801 7200 1800 1209600 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0