Apex domains cannot have CNAME records.
Question and response
Question
dig any-cdns.net. NS
Answer
any-cdns.net. 2 NS ns2.any-cdns.net.
any-cdns.net. 2 NS ns1.any-cdns.net.
Authority
The response has no authority records.
Additional
ns1.any-cdns.net. 2 A 94.156.2.15
ns2.any-cdns.net. 2 A 94.156.2.16
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0