mx3.orangecyberdefense.com has no CNAME records.
Question and response
Question
dig mx3.orangecyberdefense.com. NS
Answer
The response has no answer records.
Authority
orangecyberdefense.com. 3600 SOA dns1.equant.net. dns\.operations.orange.com. 2021121494 1200 300 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0