dk.customer.tdc.net has no MX records.
Question and response
Question
dig dk.customer.tdc.net. MX
Answer
The response has no answer records.
Authority
dk.customer.tdc.net. 3600 SOA auth05.ns.tdc.net. dns.eng.tdc.net. 2026022100 43200 3600 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0