Apex domains cannot have CNAME records.
Question and response
Question
dig vergic.com. NS
Answer
vergic.com. 5 NS ns-290.awsdns-36.com.
vergic.com. 5 NS ns-1725.awsdns-23.co.uk.
vergic.com. 5 NS ns-1530.awsdns-63.org.
vergic.com. 5 NS ns-521.awsdns-01.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0