Apex domains cannot have CNAME records.
Question and response
Question
dig Za. NS
Answer
za. 2 NS za1.dnsnode.net.
za. 2 NS nsza.is.co.za.
za. 2 NS za-ns.anycast.pch.net.
Authority
The response has no authority records.
Additional
nsza.is.co.za. 11855 A 196.4.160.27
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0