Apex domains cannot have CNAME records.
Question and response
Question
dig infimail.com. NS
Answer
infimail.com. 4 NS ns3.netcore.co.in.
infimail.com. 4 NS ns1.netcore.co.in.
infimail.com. 4 NS ns4.netcore.co.in.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0