Apex domains cannot have CNAME records.
Question and response
Question
dig ip-osteraker.se. NS
Answer
ip-osteraker.se. 5 NS ns2.teknikbyran.com.
ip-osteraker.se. 5 NS ns1.teknikbyran.com.
Authority
The response has no authority records.
Additional
ns1.teknikbyran.com. 5 A 194.48.213.14
ns2.teknikbyran.com. 5 A 91.190.139.4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0