Apex domains cannot have CNAME records.
Question and response
Question
dig necoss.net. NS
Answer
necoss.net. 5 NS ns1.starnet.cz.
necoss.net. 5 NS ns2.starnet.cz.
Authority
The response has no authority records.
Additional
ns1.starnet.cz. 5 A 92.62.224.69
ns2.starnet.cz. 5 A 92.62.224.66
ns1.starnet.cz. 5 AAAA 2a02:768:0:1010:0:0:0:3
ns2.starnet.cz. 5 AAAA 2a02:768:0:1010:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0