Apex domains cannot have CNAME records.
Question and response
Question
dig datainfosys.net. NS
Answer
datainfosys.net. 3 NS ns1.dildns.com.
datainfosys.net. 3 NS dil.datainfosys.net.
datainfosys.net. 3 NS ns2.dildns.com.
Authority
The response has no authority records.
Additional
dil.datainfosys.net. 3 A 202.157.83.3
ns1.dildns.com. 1 A 202.157.87.68
ns2.dildns.com. 1 A 202.157.83.3
ns1.dildns.com. 2 AAAA 2402:8c00:2:0:0:0:0:4
ns2.dildns.com. 1 AAAA 2402:8c00:0:1:0:0:0:3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0