Apex domains cannot have CNAME records.
Question and response
Question
dig geoscience.org.za. NS
Answer
geoscience.org.za. 5 NS ns2.lexsynergy.us.
geoscience.org.za. 5 NS ns1.lexsynergy.net.
geoscience.org.za. 5 NS ns3.lexsynergy.info.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0