mail2.leonix.fr has no CNAME records.
Question and response
Question
dig mail2.leonix.fr. NS
Answer
The response has no answer records.
Authority
leonix.fr. 300 SOA ns1.leonix.fr. hostmaster.leonix.fr. 2026030300 21600 3600 691200 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0