Apex domains cannot have CNAME records.
Question and response
Question
dig ac.za. NS
Answer
ac.za. 5 NS ns2.dns.net.za.
ac.za. 5 NS za-ns.anycast.pch.net.
ac.za. 5 NS ns2us.dns.business.
ac.za. 5 NS disa.tenet.ac.za.
Authority
The response has no authority records.
Additional
ns2.dns.net.za. 1 A 196.29.59.175
ns2us.dns.business. 1 A 147.135.106.236
ns2.dns.net.za. 1 AAAA 2001:43f8:790:5901:0:0:c41d:3baf
ns2us.dns.business. 1 AAAA 2604:2dc0:200:2eb:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0