mx2.site-internet.com has no CNAME records.
Question and response
Question
dig mx2.site-internet.com. NS
Answer
The response has no answer records.
Authority
site-internet.com. 335 SOA ns76.site-internet.com. hebergement.platine.com. 2026021200 10800 3600 1209600 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0