mx1.protect.cienum.fr has no CNAME records.
Question and response
Question
dig mx1.protect.cienum.fr. NS
Answer
The response has no answer records.
Authority
cienum.fr. 10666 SOA ns3.rmi.fr. ndd.adista.fr. 2023012502 21600 3600 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0