www.is-dev.nl has no MX records.
Question and response
Question
dig www.is-dev.nl. MX
Answer
The response has no answer records.
Authority
nl. 600 SOA ns1.dns.nl. dns.sidn.nl. 2026022312 3600 600 1209600 600
Additional
. 0 OPT ; payload 1400, xrcode 0, version 0, flags 0