Apex domains cannot have CNAME records.
Question and response
Question
dig norid.no. NS
Answer
norid.no. 5 NS auth02.osl.ns.norid.no.
norid.no. 5 NS y.nic.no.
norid.no. 5 NS auth01.trd.ns.norid.no.
norid.no. 5 NS z.nic.no.
norid.no. 5 NS auth03.svg.ns.norid.no.
Authority
The response has no authority records.
Additional
y.nic.no. 171754 A 193.75.4.22
z.nic.no. 171754 A 158.38.8.133
auth01.trd.ns.norid.no. 5 A 91.209.215.53
auth02.osl.ns.norid.no. 5 A 128.39.8.53
auth03.svg.ns.norid.no. 5 A 5.183.79.53
y.nic.no. 171754 AAAA 2001:8c0:8200:1:0:0:0:2
z.nic.no. 171754 AAAA 2001:700:0:52d:158:38:8:133
auth01.trd.ns.norid.no. 5 AAAA 2001:700:4600:104:0:0:0:53
auth02.osl.ns.norid.no. 5 AAAA 2001:700:0:412f:0:0:0:53
auth03.svg.ns.norid.no. 5 AAAA 2001:700:5d00:104:0:0:0:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0