Apex domains cannot have CNAME records.
Question and response
Question
dig estartupbusiness.com. NS
Answer
estartupbusiness.com. 5 NS ns-1506.awsdns-60.org.
estartupbusiness.com. 5 NS ns-1528.awsdns-63.org.
estartupbusiness.com. 5 NS ns-1993.awsdns-57.co.uk.
estartupbusiness.com. 5 NS ns-127.awsdns-15.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0