rev.linkbynet.com has no MX records.
Question and response
Question
dig rev.linkbynet.com. MX
Answer
The response has no answer records.
Authority
rev.linkbynet.com. 1800 SOA ns1.linkbynet.com. administrateur.lbn.fr. 2025111906 21600 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0