b4-11.cdns.net has no CNAME records.
Question and response
Question
dig b4-11.cdns.net. NS
Answer
The response has no answer records.
Authority
cdns.net. 1767 SOA dns1.cdns.net. admin.communitydns.net. 1772339690 900 400 3600000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0