ns3.linkbynet.com has no MX records.
Question and response
Question
dig ns3.linkbynet.com. MX
Answer
The response has no answer records.
Authority
linkbynet.com. 60 SOA ns1.linkbynet.com. administrateur.lbn.fr. 2026020401 1800 604800 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0