dns1.mts.net has no MX records.
Question and response
Question
dig dns1.mts.net. MX
Answer
The response has no answer records.
Authority
mts.net. 900 SOA dns1.mts.net. dnsadmin.bellmts.net. 2014071790 10800 3600 2419200 900
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0