Apex domains cannot have CNAME records.
Question and response
Question
dig uninett.no. NS
Answer
uninett.no. 5 NS nn.uninett.no.
uninett.no. 5 NS benoni.uit.no.
uninett.no. 5 NS ns.uninett.no.
uninett.no. 5 NS nac.no.
uninett.no. 5 NS server.nordu.net.
Authority
The response has no authority records.
Additional
nn.uninett.no. 5 A 158.38.0.181
ns.uninett.no. 5 A 158.38.3.139
nac.no. 5 A 128.39.2.22
benoni.uit.no. 5 A 129.242.4.254
server.nordu.net. 5 A 193.10.252.19
nn.uninett.no. 5 AAAA 2001:700:0:503:0:0:aa:5302
ns.uninett.no. 5 AAAA 2001:700:1:12:0:0:3:139
nac.no. 5 AAAA 2001:700:0:102:0:0:0:aa53
server.nordu.net. 5 AAAA 2001:948:4:2:0:0:0:19
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0