mail.nsauth2.trans-ix.net has no MX records.
Question and response
Question
dig mail.nsauth2.trans-ix.net. MX
Answer
The response has no answer records.
Authority
nsauth2.trans-ix.net. 3600 SOA nsauth1.trans-ix.nl. root.nsauth2.trans-ix.net. 2025040100 3600 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0