Apex domains cannot have CNAME records.
Question and response
Question
dig d3ek0l3dods6u.cloudfront.net. NS
Answer
d3ek0l3dods6u.cloudfront.net. 5 NS ns-770.awsdns-32.net.
d3ek0l3dods6u.cloudfront.net. 5 NS ns-1634.awsdns-12.co.uk.
d3ek0l3dods6u.cloudfront.net. 5 NS ns-449.awsdns-56.com.
d3ek0l3dods6u.cloudfront.net. 5 NS ns-1478.awsdns-56.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0