Apex domains cannot have CNAME records.
Question and response
Question
dig cisko.se. NS
Answer
cisko.se. 5 NS jay.ns.cloudflare.com.
cisko.se. 5 NS gail.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0