mail.hctc.net has no CNAME records.
Question and response
Question
dig mail.hctc.net. NS
Answer
The response has no answer records.
Authority
hctc.net. 4916 SOA infobloxcmft-gmc.hctc.coop. hostmaster.hctc.net. 2015030812 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0