dnsb.nic.microsoft has no CNAME records.
Question and response
Question
dig dnsb.nic.microsoft. NS
Answer
The response has no answer records.
Authority
nic.microsoft. 3600 SOA dns1.nic.microsoft. hostmaster.nominet.org.uk. 1698252657 900 300 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0