Apex domains cannot have CNAME records.
Question and response
Question
dig nerke.za.net. NS
Answer
nerke.za.net. 5 NS jonah.ns.cloudflare.com.
nerke.za.net. 5 NS stella.ns.cloudflare.com.
nerke.za.net. 5 NS ns1.ziec.name.
nerke.za.net. 5 NS ns5.sileman.pl.
Authority
The response has no authority records.
Additional
ns5.sileman.pl. 5 A 85.11.65.254
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0