Apex domains cannot have CNAME records.
Question and response
Question
dig rajeevtiwari.com. NS
Answer
rajeevtiwari.com. 5 NS ns1.rajeevtiwari.com.
rajeevtiwari.com. 5 NS ns2.rajeevtiwari.com.
Authority
The response has no authority records.
Additional
ns1.rajeevtiwari.com. 5 A 167.114.174.24
ns2.rajeevtiwari.com. 5 A 51.161.71.188
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0