Apex domains cannot have CNAME records.
Question and response
Question
dig bluedotdevelop.com. NS
Answer
bluedotdevelop.com. 3 NS ns-1155.awsdns-16.org.
bluedotdevelop.com. 3 NS ns-257.awsdns-32.com.
bluedotdevelop.com. 3 NS ns-205.awsdns-25.com.
bluedotdevelop.com. 3 NS ns-1679.awsdns-17.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0