Apex domains cannot have CNAME records.
Question and response
Question
dig alltele.net. NS
Answer
alltele.net. 5 NS ns1.driftkund.se.
alltele.net. 5 NS ns2.driftkund.se.
alltele.net. 5 NS ns3.driftkund.se.
alltele.net. 5 NS ns4.driftkund.se.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0