dns-01.smartape.net has no MX records.
Question and response
Question
dig dns-01.smartape.net. MX
Answer
The response has no answer records.
Authority
smartape.net. 3600 SOA ns3.smartape.net. abuse.smartape.net. 2013041697 3600 7200 2419200 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0