Apex domains cannot have CNAME records.
Question and response
Question
dig eon.com. NS
Answer
eon.com. 5 NS ns0166.secondary.cloudflare.com.
eon.com. 5 NS ns0009.secondary.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0