Apex domains cannot have CNAME records.
Question and response
Question
dig acemdns.com. NS
Answer
acemdns.com. 4 NS ns-1877.awsdns-42.co.uk.
acemdns.com. 4 NS ns-1481.awsdns-57.org.
acemdns.com. 4 NS ns-84.awsdns-10.com.
acemdns.com. 4 NS ns-650.awsdns-17.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0