Apex domains cannot have CNAME records.
Question and response
Question
dig s3-website.us-east-1.amazonaws.com. NS
Answer
s3-website.us-east-1.amazonaws.com. 5 NS ns-1779.awsdns-30.co.uk.
s3-website.us-east-1.amazonaws.com. 5 NS ns-437.awsdns-54.com.
s3-website.us-east-1.amazonaws.com. 5 NS ns-611.awsdns-12.net.
s3-website.us-east-1.amazonaws.com. 5 NS ns-1286.awsdns-32.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0