Apex domains cannot have CNAME records.
Question and response
Question
dig xalventora.com. NS
Answer
xalventora.com. 5 NS ns-1315.awsdns-36.org.
xalventora.com. 5 NS ns-1659.awsdns-15.co.uk.
xalventora.com. 5 NS ns-498.awsdns-62.com.
xalventora.com. 5 NS ns-909.awsdns-49.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0