Apex domains cannot have CNAME records.
Question and response
Question
dig dicey.org. NS
Answer
dicey.org. 5 NS ns-710.awsdns-24.net.
dicey.org. 5 NS ns-162.awsdns-20.com.
dicey.org. 5 NS ns-1590.awsdns-06.co.uk.
dicey.org. 5 NS ns-1305.awsdns-35.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0