Apex domains cannot have CNAME records.
Question and response
Question
dig vtoasp.net. NS
Answer
vtoasp.net. 5 NS ns3.ouludc.fi.
vtoasp.net. 5 NS ns1.ouludc.fi.
Authority
The response has no authority records.
Additional
ns1.ouludc.fi. 5 A 185.55.176.8
ns3.ouludc.fi. 5 A 51.144.144.173
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0