Apex domains cannot have CNAME records.
Question and response
Question
dig equifaxsd.ivcert.net. NS
Answer
equifaxsd.ivcert.net. 5 NS ns-709.awsdns-24.net.
equifaxsd.ivcert.net. 5 NS ns-1116.awsdns-11.org.
equifaxsd.ivcert.net. 5 NS ns-2028.awsdns-61.co.uk.
equifaxsd.ivcert.net. 5 NS ns-248.awsdns-31.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0