Apex domains cannot have CNAME records.
Question and response
Question
dig bigpoint.com. NS
Answer
bigpoint.com. 5 NS ns-406.awsdns-50.com.
bigpoint.com. 5 NS ns-968.awsdns-57.net.
bigpoint.com. 5 NS ns-1330.awsdns-38.org.
bigpoint.com. 5 NS ns-1641.awsdns-13.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0