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