smtp01.d2ms.com has no CNAME records.
Question and response
Question
dig smtp01.d2ms.com. NS
Answer
The response has no answer records.
Authority
d2ms.com. 2520 SOA ns1-06.azure-dns.com. hostmaster.webd2ms.com. 243 2400 600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0