Apex domains cannot have CNAME records.
Question and response
Question
dig infracom.se. NS
Answer
infracom.se. 5 NS ns2.pin.se.
infracom.se. 5 NS ns3.pin.se.
infracom.se. 5 NS ns1.pin.se.
Authority
The response has no authority records.
Additional
ns1.pin.se. 5 A 81.93.130.6
ns2.pin.se. 5 A 81.93.131.6
ns3.pin.se. 5 A 89.189.220.99
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0