mx1.morganstanley.com has no CNAME records.
Question and response
Question
dig mx1.morganstanley.com. NS
Answer
The response has no answer records.
Authority
morganstanley.com. 3384 SOA ext-ns1.morganstanley.net. postmaster.ms.com. 39826 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0