Apex domains cannot have CNAME records.
Question and response
Question
dig aonet.co.za. NS
Answer
aonet.co.za. 4 NS ns02.glodns.net.
aonet.co.za. 4 NS ns01.glodns.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0