dns1.p01.nsone.net has no MX records.
Question and response
Question
dig dns1.p01.nsone.net. MX
Answer
The response has no answer records.
Authority
nsone.net. 3600 SOA dns1.p01.nsone.net. hostmaster.nsone.net. 1736533684 43200 7200 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0