MTA-232.ncdelivery01.com has no CNAME records.
Question and response
Question
dig MTA-232.ncdelivery01.com. NS
Answer
The response has no answer records.
Authority
ncdelivery01.com. 10800 SOA ns1.dnsbolt.com. Postmaster.ncdelivery01.com. 643828600 10800 3600 172800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0