Apex domains cannot have CNAME records.
Question and response
Question
dig se.vkube.cloud. NS
Answer
se.vkube.cloud. 5 NS ns-6.awsdns-00.com.
se.vkube.cloud. 5 NS ns-697.awsdns-23.net.
se.vkube.cloud. 5 NS ns-1317.awsdns-36.org.
se.vkube.cloud. 5 NS ns-1975.awsdns-54.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0