mx1.lnh.corp.rcn.net has no CNAME records.
Question and response
Question
dig mx1.lnh.corp.rcn.net. NS
Answer
The response has no answer records.
Authority
corp.rcn.net. 484 SOA master.dns.rcn.net. hostmaster.rcn.com. 2025091503 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0