Apex domains cannot have CNAME records.
Question and response
Question
dig d3r5ijyey97a79.cloudfront.net. NS
Answer
d3r5ijyey97a79.cloudfront.net. 5 NS ns-2026.awsdns-61.co.uk.
d3r5ijyey97a79.cloudfront.net. 5 NS ns-883.awsdns-46.net.
d3r5ijyey97a79.cloudfront.net. 5 NS ns-137.awsdns-17.com.
d3r5ijyey97a79.cloudfront.net. 5 NS ns-1051.awsdns-03.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0