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