Apex domains cannot have CNAME records.
Question and response
Question
dig lby.se. NS
Answer
lby.se. 4 NS ns1.irc-net.se.
lby.se. 4 NS ns2.irc-net.se.
Authority
The response has no authority records.
Additional
ns1.irc-net.se. 4 A 217.197.56.130
ns2.irc-net.se. 4 A 217.197.56.133
ns1.irc-net.se. 4 AAAA 2a13:d480:9:10:0:0:0:130
ns2.irc-net.se. 4 AAAA 2a13:d480:9:10:0:0:0:133
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0