mx1.orangecyberdefense.com has no CNAME records.
Question and response
Question
dig mx1.orangecyberdefense.com. NS
Answer
The response has no answer records.
Authority
orangecyberdefense.com. 2884 SOA dns1.equant.net. dns\.operations.orange.com. 2021121502 1200 300 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0