Apex domains cannot have CNAME records.
Question and response
Question
dig ip-zone.com. NS
Answer
ip-zone.com. 2 NS olga.ns.cloudflare.com.
ip-zone.com. 2 NS tim.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0