dns1.vps.net has no MX records.
Question and response
Question
dig dns1.vps.net. MX
Answer
The response has no answer records.
Authority
dns1.vps.net. 43200 SOA dns1.vps.net. root.softlayer.com. 2018022300 7200 600 1728000 43200
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0