Apex domains cannot have CNAME records.
Question and response
Question
dig amazonaws.info. NS
Answer
amazonaws.info. 5 NS ns2.amzndns.com.
amazonaws.info. 5 NS ns1.amzndns.net.
amazonaws.info. 5 NS ns1.amzndns.co.uk.
amazonaws.info. 5 NS ns2.amzndns.co.uk.
amazonaws.info. 5 NS ns1.amzndns.com.
amazonaws.info. 5 NS ns1.amzndns.org.
amazonaws.info. 5 NS ns2.amzndns.org.
amazonaws.info. 5 NS ns2.amzndns.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0