rnc.net.cable.rogers.com has no MX records.
Question and response
Question
dig rnc.net.cable.rogers.com. MX
Answer
The response has no answer records.
Authority
rnc.net.cable.rogers.com. 900 SOA pub1-master1-iblox-wlfdle.mgmt.net.rogers.com. cnrbacc.rci.rogers.com. 1 10800 3600 2419200 900
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0