Apex domains cannot have CNAME records.
Question and response
Question
dig zulmarix.com. NS
Answer
zulmarix.com. 5 NS ns-141.awsdns-17.com.
zulmarix.com. 5 NS ns-927.awsdns-51.net.
zulmarix.com. 5 NS ns-1749.awsdns-26.co.uk.
zulmarix.com. 5 NS ns-93.awsdns-11.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0