Apex domains cannot have CNAME records.
Question and response
Question
dig ti.telenor.net. NS
Answer
ti.telenor.net. 5 NS ns2.nextra.no.
ti.telenor.net. 5 NS nn.uninett.no.
ti.telenor.net. 5 NS lft.ti.telenor.net.
Authority
The response has no authority records.
Additional
nn.uninett.no. 4 A 158.38.0.181
ns2.nextra.no. 4 A 148.122.161.2
nn.uninett.no. 4 AAAA 2001:700:0:503:0:0:aa:5302
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0