Apex domains cannot have CNAME records.
Question and response
Question
dig registry.net.za. NS
Answer
registry.net.za. 5 NS ns1.dnservices.co.za.
registry.net.za. 5 NS ns1.dns.net.za.
registry.net.za. 5 NS ns2us.dns.business.
Authority
The response has no authority records.
Additional
ns1.dnservices.co.za. 5 A 206.223.136.167
ns2us.dns.business. 5 A 147.135.106.236
ns2us.dns.business. 5 AAAA 2604:2dc0:200:2eb:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0