Apex domains cannot have CNAME records.
Question and response
Question
dig cubric.gr. NS
Answer
cubric.gr. 5 NS jack.ns.cloudflare.com.
cubric.gr. 5 NS aleena.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0