mx79.webindustrie.fr has no CNAME records.
Question and response
Question
dig mx79.webindustrie.fr. NS
Answer
The response has no answer records.
Authority
webindustrie.fr. 0 SOA ns1.cyres.fr. root.cyres.fr. 0 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0