Apex domains cannot have CNAME records.
Question and response
Question
dig acip42.com. NS
Answer
acip42.com. 5 NS ns-1821.awsdns-35.co.uk.
acip42.com. 5 NS ns-1554.awsdns-02.co.uk.
acip42.com. 5 NS ns-1137.awsdns-14.org.
acip42.com. 5 NS ns-1452.awsdns-53.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0