Apex domains cannot have CNAME records.
Question and response
Question
dig extrasheet.com. NS
Answer
extrasheet.com. 5 NS ns-1952.awsdns-52.co.uk.
extrasheet.com. 5 NS ns-25.awsdns-03.com.
extrasheet.com. 5 NS ns-931.awsdns-52.net.
extrasheet.com. 5 NS ns-1041.awsdns-02.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0