Apex domains cannot have CNAME records.
Question and response
Question
dig turknet.io. NS
Answer
turknet.io. 5 NS ns.turknet.io.
turknet.io. 5 NS ns.turknet.net.tr.
turknet.io. 5 NS ns.turk.net.
Authority
The response has no authority records.
Additional
ns.turk.net. 5 A 193.192.100.10
ns.turknet.io. 5 A 20.229.126.11
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0