Apex domains cannot have CNAME records.
Question and response
Question
dig equifaxsd.pre.ivcert.net. NS
Answer
equifaxsd.pre.ivcert.net. 5 NS ns-626.awsdns-14.net.
equifaxsd.pre.ivcert.net. 5 NS ns-1841.awsdns-38.co.uk.
equifaxsd.pre.ivcert.net. 5 NS ns-260.awsdns-32.com.
equifaxsd.pre.ivcert.net. 5 NS ns-1508.awsdns-60.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0