smtp.cines.fr has no CNAME records.
Question and response
Question
dig smtp.cines.fr. NS
Answer
The response has no answer records.
Authority
cines.fr. 3600 SOA cnudns.cines.fr. postmaster.cines.fr. 2026022766 21600 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0