contaboserver.net has no MX records.
Question and response
Question
dig contaboserver.net. MX
Answer
The response has no answer records.
Authority
contaboserver.net. 3600 SOA ns1.contabo.net. hostmaster.contabo.de. 1771737527 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0