ftrmail01.ftr.com has no CNAME records.
Question and response
Question
dig ftrmail01.ftr.com. NS
Answer
The response has no answer records.
Authority
ftr.com. 3600 SOA auth.roch.ny.frontiernet.net. hostmaster.frontier.com. 2602270003 900 300 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0