mrf.va.web.rcn.net has no MX records.
Question and response
Question
dig mrf.va.web.rcn.net. MX
Answer
The response has no answer records.
Authority
mrf.va.web.rcn.net. 3600 SOA master.dns.rcn.net. hostmaster.rcn.com. 2016021201 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0