dev.whiteworks.nl has no MX records.
Question and response
Question
dig dev.whiteworks.nl. MX
Answer
The response has no answer records.
Authority
whiteworks.nl. 3600 SOA ns3.combell.net. hostmaster.whiteworks.nl. 1769413181 10800 3600 604800 40000
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0