Apex domains cannot have CNAME records.
Question and response
Question
dig s3-deprecated.sa-east-1.amazonaws.com. NS
Answer
s3-deprecated.sa-east-1.amazonaws.com. 5 NS ns-1009.awsdns-62.net.
s3-deprecated.sa-east-1.amazonaws.com. 5 NS ns-1999.awsdns-57.co.uk.
s3-deprecated.sa-east-1.amazonaws.com. 5 NS ns-30.awsdns-03.com.
s3-deprecated.sa-east-1.amazonaws.com. 5 NS ns-1513.awsdns-61.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0