Apex domains cannot have CNAME records.
Question and response
Question
dig incognitomail.co. NS
Answer
incognitomail.co. 5 NS ziggy.ns.cloudflare.com.
incognitomail.co. 5 NS huxley.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0