Apex domains cannot have CNAME records.
Question and response
Question
dig rjheywood.com. NS
Answer
rjheywood.com. 5 NS ns-642.awsdns-16.net.
rjheywood.com. 5 NS ns-1028.awsdns-00.org.
rjheywood.com. 5 NS ns-854.awsdns-42.net.
rjheywood.com. 5 NS ns-1958.awsdns-52.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0