Apex domains cannot have CNAME records.
Question and response
Question
dig telenor.net. NS
Answer
telenor.net. 5 NS ns1.nextra.no.
telenor.net. 5 NS nn.uninett.no.
telenor.net. 5 NS ns2.nextra.no.
Authority
The response has no authority records.
Additional
nn.uninett.no. 5 A 158.38.0.181
ns1.nextra.no. 5 A 148.122.208.98
ns2.nextra.no. 5 A 148.122.161.2
nn.uninett.no. 5 AAAA 2001:700:0:503:0:0:aa:5302
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0