nsauth03.solcon.net has no MX records.
Question and response
Question
dig nsauth03.solcon.net. MX
Answer
The response has no answer records.
Authority
solcon.net. 3600 SOA nsauth01.solcon.nl. postmaster.solcon.nl. 2026021803 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0