Apex domains cannot have CNAME records.
Question and response
Question
dig netxinternet.com. NS
Answer
netxinternet.com. 5 NS ns3.netxinternet.com.
netxinternet.com. 5 NS ns1.netxinternet.com.
netxinternet.com. 5 NS ns2.netxinternet.com.
netxinternet.com. 5 NS ns4.netxinternet.com.
Authority
The response has no authority records.
Additional
ns1.netxinternet.com. 5 A 208.88.44.6
ns2.netxinternet.com. 5 A 23.132.112.15
ns3.netxinternet.com. 5 A 208.88.44.8
ns4.netxinternet.com. 5 A 23.132.112.17
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0