Apex domains cannot have CNAME records.
Question and response
Question
dig navex.com. NS
Answer
navex.com. 5 NS ns-119.awsdns-14.com.
navex.com. 5 NS ns-1789.awsdns-31.co.uk.
navex.com. 5 NS ns-1504.awsdns-60.org.
navex.com. 5 NS ns-721.awsdns-26.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0