Apex domains cannot have CNAME records.
Question and response
Question
dig dmarc-dns.com. NS
Answer
dmarc-dns.com. 3 NS ns-1747.awsdns-26.co.uk.
dmarc-dns.com. 3 NS ns-437.awsdns-54.com.
dmarc-dns.com. 3 NS ns-680.awsdns-21.net.
dmarc-dns.com. 3 NS ns-1185.awsdns-20.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0