Apex domains cannot have CNAME records.
Question and response
Question
dig amazonses.com. NS
Answer
amazonses.com. 5 NS ns-1722.awsdns-23.co.uk.
amazonses.com. 5 NS ns-1130.awsdns-13.org.
amazonses.com. 5 NS ns-265.awsdns-33.com.
amazonses.com. 5 NS ns-882.awsdns-46.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0