Apex domains cannot have CNAME records.
Question and response
Question
dig equifax.pre.ivcert.net. NS
Answer
equifax.pre.ivcert.net. 5 NS ns-778.awsdns-33.net.
equifax.pre.ivcert.net. 5 NS ns-1807.awsdns-33.co.uk.
equifax.pre.ivcert.net. 5 NS ns-30.awsdns-03.com.
equifax.pre.ivcert.net. 5 NS ns-1044.awsdns-02.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0