Apex domains cannot have CNAME records.
Question and response
Question
dig acems1.com. NS
Answer
acems1.com. 5 NS ns-1684.awsdns-18.co.uk.
acems1.com. 5 NS ns-560.awsdns-06.net.
acems1.com. 5 NS ns-116.awsdns-14.com.
acems1.com. 5 NS ns-1055.awsdns-03.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0