dnsa.nic.microsoft has no CNAME records.
Question and response
Question
dig dnsa.nic.microsoft. NS
Answer
The response has no answer records.
Authority
nic.microsoft. 3600 SOA dns1.nic.microsoft. hostmaster.nominet.org.uk. 1698252656 900 300 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0