Apex domains cannot have CNAME records.
Question and response
Question
dig se. NS
Answer
se. 5 NS b.ns.se.
se. 5 NS g.ns.se.
se. 5 NS f.ns.se.
se. 5 NS m.ns.se.
se. 5 NS x.ns.se.
se. 5 NS c.ns.se.
se. 5 NS a.ns.se.
se. 5 NS i.ns.se.
se. 5 NS z.ns.se.
se. 5 NS y.ns.se.
Authority
The response has no authority records.
Additional
a.ns.se. 152774 A 192.36.144.107
b.ns.se. 152749 A 192.36.133.107
c.ns.se. 157391 A 192.36.135.107
f.ns.se. 152749 A 192.36.134.97
g.ns.se. 152744 A 194.68.134.97
i.ns.se. 61863 A 194.146.106.22
m.ns.se. 152644 A 194.0.11.112
x.ns.se. 162488 A 213.108.25.4
y.ns.se. 162326 A 185.159.197.150
z.ns.se. 157459 A 185.159.198.150
a.ns.se. 152774 AAAA 2a01:3f0:0:301:0:0:0:53
b.ns.se. 152749 AAAA 2001:67c:254c:301:0:0:0:53
c.ns.se. 157391 AAAA 2001:67c:2554:301:0:0:0:53
f.ns.se. 152749 AAAA 2001:67c:2550:301:0:0:0:53
g.ns.se. 152744 AAAA 2001:67c:2558:301:0:0:0:53
i.ns.se. 61863 AAAA 2001:67c:1010:5:0:0:0:53
m.ns.se. 152644 AAAA 2001:678:e:112:0:0:0:53
x.ns.se. 162488 AAAA 2001:67c:124c:e000:0:0:0:4
y.ns.se. 162326 AAAA 2620:10a:80aa:0:0:0:0:150
z.ns.se. 157459 AAAA 2620:10a:80ab:0:0:0:0:150
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0