Apex domains cannot have CNAME records.
Question and response
Question
dig us-west-2.compute.amazonaws.com. NS
Answer
us-west-2.compute.amazonaws.com. 5 NS ns-472.awsdns-59.com.
us-west-2.compute.amazonaws.com. 5 NS ns-625.awsdns-14.net.
us-west-2.compute.amazonaws.com. 5 NS ns-1477.awsdns-56.org.
us-west-2.compute.amazonaws.com. 5 NS ns-2021.awsdns-60.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0