Apex domains cannot have CNAME records.
Question and response
Question
dig noackhostingab.se. NS
Answer
noackhostingab.se. 5 NS dns4.fxs.se.
noackhostingab.se. 5 NS dns-anycast.no-ack.net.
noackhostingab.se. 5 NS dns3.fxs.se.
noackhostingab.se. 5 NS dns5.fxs.se.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0