zimbra.42sec.net has no MX records.
Question and response
Question
dig zimbra.42sec.net. MX
Answer
The response has no answer records.
Authority
42sec.net. 300 SOA ns0.transip.nl. hostmaster.transip.nl. 2026022000 86400 1800 2419200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0