Apex domains cannot have CNAME records.
Question and response
Question
dig aftertomorrow.net. NS
Answer
aftertomorrow.net. 5 NS ns-942.awsdns-53.net.
aftertomorrow.net. 5 NS ns-522.awsdns-01.net.
aftertomorrow.net. 5 NS ns-644.awsdns-16.net.
aftertomorrow.net. 5 NS ns-1528.awsdns-63.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0