mx2.integral-mail.fr has no CNAME records.
Question and response
Question
dig mx2.integral-mail.fr. NS
Answer
The response has no answer records.
Authority
fr. 600 SOA a.nic.fr. dnsmaster.afnic.fr. 2244358302 3600 1800 1209600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0