Apex domains cannot have CNAME records.
Question and response
Question
dig tlabs.ac.za. NS
Answer
tlabs.ac.za. 5 NS ashton.ns.cloudflare.com.
tlabs.ac.za. 5 NS coraline.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0