Apex domains cannot have CNAME records.
Question and response
Question
dig cy. NS
Answer
cy. 5 NS ns4.apnic.net.
cy. 5 NS cynic6.dns.cy.
cy. 5 NS cy-ns.anycast.pch.net.
cy. 5 NS estia.ics.forth.gr.
cy. 5 NS cynic4.dns.cy.
cy. 5 NS ns31.rcode0.net.
Authority
The response has no authority records.
Additional
ns4.apnic.net. 5 A 202.12.31.53
estia.ics.forth.gr. 167619 A 139.91.191.3
cynic4.dns.cy. 172291 A 194.42.29.16
cynic6.dns.cy. 172291 A 194.42.29.5
ns4.apnic.net. 5 AAAA 2001:dd8:12:0:0:0:0:53
estia.ics.forth.gr. 172384 AAAA 2001:648:2c30:0:0:0:191:3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0