Apex domains cannot have CNAME records.
Question and response
Question
dig petcksa.com. NS
Answer
petcksa.com. 5 NS ns-1048.awsdns-03.org.
petcksa.com. 5 NS ns-1633.awsdns-12.co.uk.
petcksa.com. 5 NS ns-1315.awsdns-36.org.
petcksa.com. 5 NS ns-1195.awsdns-21.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0