outbound6.mail.transip.nl has no MX records.
Question and response
Question
dig outbound6.mail.transip.nl. MX
Answer
The response has no answer records.
Authority
transip.nl. 300 SOA ns0.transip.net. hostmaster.transip.nl. 2026022403 300 60 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0