Apex domains cannot have CNAME records.
Question and response
Question
dig clubcorp.com. NS
Answer
clubcorp.com. 5 NS ns-487.awsdns-60.com.
clubcorp.com. 5 NS ns-1515.awsdns-61.org.
clubcorp.com. 5 NS ns-711.awsdns-24.net.
clubcorp.com. 5 NS ns-1650.awsdns-14.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0