nsauth3.interconnect-dns.be has no MX records.
Question and response
Question
dig nsauth3.interconnect-dns.be. MX
Answer
The response has no answer records.
Authority
interconnect-dns.be. 3600 SOA nsauth1.interconnect-dns.be. postmaster.interconnect.nl. 2020031000 14400 1800 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0