Apex domains cannot have CNAME records.
Question and response
Question
dig simiblues.org. NS
Answer
simiblues.org. 4 NS ns-295.awsdns-36.com.
simiblues.org. 4 NS ns-1178.awsdns-19.org.
simiblues.org. 4 NS ns-1715.awsdns-22.co.uk.
simiblues.org. 4 NS ns-1916.awsdns-47.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0