Apex domains cannot have CNAME records.
Question and response
Question
dig vhzmpjdqfx.acm-validations.aws. NS
Answer
vhzmpjdqfx.acm-validations.aws. 5 NS ns-829.awsdns-39.net.
vhzmpjdqfx.acm-validations.aws. 5 NS ns-1699.awsdns-20.co.uk.
vhzmpjdqfx.acm-validations.aws. 5 NS ns-362.awsdns-45.com.
vhzmpjdqfx.acm-validations.aws. 5 NS ns-1063.awsdns-04.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0