Apex domains cannot have CNAME records.
Question and response
Question
dig vkube.cloud. NS
Answer
vkube.cloud. 1 NS ns-285.awsdns-35.com.
vkube.cloud. 1 NS ns-1603.awsdns-08.co.uk.
vkube.cloud. 1 NS ns-1473.awsdns-56.org.
vkube.cloud. 1 NS ns-908.awsdns-49.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0