Apex domains cannot have CNAME records.
Question and response
Question
dig sansan.com. NS
Answer
sansan.com. 5 NS ns-1982.awsdns-55.co.uk.
sansan.com. 5 NS ns-1295.awsdns-33.org.
sansan.com. 5 NS ns-241.awsdns-30.com.
sansan.com. 5 NS ns-623.awsdns-13.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0