auth3.keensystems.nl has no MX records.
Question and response
Question
dig auth3.keensystems.nl. MX
Answer
The response has no answer records.
Authority
keensystems.nl. 28800 SOA auth1.keensystems.eu. dns-admin.keensystems.net. 2026030301 14400 1800 604800 28800
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0