Apex domains cannot have CNAME records.
Question and response
Question
dig dnsv4.net. NS
Answer
dnsv4.net. 5 NS ns3.dnsv4.com.
dnsv4.net. 5 NS ns4.dnsv4.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0