Apex domains cannot have CNAME records.
Question and response
Question
dig hostek.se. NS
Answer
hostek.se. 5 NS ns4.hostek.se.
hostek.se. 5 NS ns3.hostek.se.
hostek.se. 5 NS ns1.hostek.se.
hostek.se. 5 NS ns2.hostek.se.
Authority
The response has no authority records.
Additional
ns1.hostek.se. 5 A 82.99.18.71
ns2.hostek.se. 5 A 94.246.96.69
ns3.hostek.se. 5 A 62.109.34.77
ns4.hostek.se. 5 A 188.40.202.4
ns1.hostek.se. 5 AAAA 2a01:2b0:301d:99:0:0:0:71
ns2.hostek.se. 5 AAAA 2a01:2b0:301d:88:0:0:0:69
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0