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