Apex domains cannot have CNAME records.
Question and response
Question
dig cloudfront.net. NS
Answer
cloudfront.net. 5 NS ns-1306.awsdns-35.org.
cloudfront.net. 5 NS ns-666.awsdns-19.net.
cloudfront.net. 5 NS ns-418.awsdns-52.com.
cloudfront.net. 5 NS ns-1597.awsdns-07.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0