Apex domains cannot have CNAME records.
Question and response
Question
dig cdnetdns.net. NS
Answer
cdnetdns.net. 5 NS b.qtlgslbcn.info.
cdnetdns.net. 5 NS b.qtlcdncn.info.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0