Apex domains cannot have CNAME records.
Question and response
Question
dig dattaweb.com. NS
Answer
dattaweb.com. 4 NS ns1.dattaweb.com.
dattaweb.com. 4 NS ns2.dattaweb.com.
Authority
The response has no authority records.
Additional
ns1.dattaweb.com. 4 A 200.58.112.194
ns2.dattaweb.com. 4 A 200.58.112.103
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0