ns2.stratoserver.net has no MX records.
Question and response
Question
dig ns2.stratoserver.net. MX
Answer
The response has no answer records.
Authority
stratoserver.net. 1800 SOA ns.stratoserver.net. hostmaster.stratoserver.net. 2020129589 10000 14400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0