Apex domains cannot have CNAME records.
Question and response
Question
dig spf.dotnetwork.co.za. NS
Answer
spf.dotnetwork.co.za. 4 NS ns1.dotnetworkdns.co.za.
spf.dotnetwork.co.za. 4 NS ns3.dotnetworkdns.co.za.
spf.dotnetwork.co.za. 4 NS ns2.dotnetworkdns.co.za.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0