Apex domains cannot have CNAME records.
Question and response
Question
dig reinvent.com. NS
Answer
reinvent.com. 5 NS ns-1079.awsdns-06.org.
reinvent.com. 5 NS ns-265.awsdns-33.com.
reinvent.com. 5 NS ns-579.awsdns-08.net.
reinvent.com. 5 NS ns-1878.awsdns-42.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0