Apex domains cannot have CNAME records.
Question and response
Question
dig padinet.com. NS
Answer
padinet.com. 4 NS ns1.padinet.com.
padinet.com. 4 NS ns3.padinet.com.
padinet.com. 4 NS ns2.padinet.com.
Authority
The response has no authority records.
Additional
ns1.padinet.com. 4 A 202.6.233.11
ns2.padinet.com. 4 A 117.102.253.44
ns3.padinet.com. 4 A 204.74.222.53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0