Apex domains cannot have CNAME records.
Question and response
Question
dig net.dewcis.com. NS
Answer
net.dewcis.com. 5 NS ns1.tamshi.com.
net.dewcis.com. 5 NS ns3.tamshi.com.
net.dewcis.com. 5 NS ns2.tamshi.com.
Authority
The response has no authority records.
Additional
ns1.tamshi.com. 5 A 102.219.23.41
ns2.tamshi.com. 5 A 134.122.88.59
ns3.tamshi.com. 5 A 102.219.23.39
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0