Apex domains cannot have CNAME records.
Question and response
Question
dig hu. NS
Answer
hu. 5 NS d.hu.
hu. 5 NS c.hu.
hu. 5 NS f.hu.
hu. 5 NS p.hu.
hu. 5 NS b.hu.
hu. 5 NS a.hu.
hu. 5 NS e.hu.
Authority
The response has no authority records.
Additional
a.hu. 166281 A 5.28.0.97
b.hu. 63459 A 193.41.82.18
c.hu. 58905 A 195.111.1.92
d.hu. 68170 A 5.28.0.99
e.hu. 74450 A 194.0.25.11
f.hu. 135907 A 194.0.9.1
p.hu. 68749 A 204.61.216.146
a.hu. 166281 AAAA 2a00:e6a0:3:1014:0:0:0:97
b.hu. 63459 AAAA 2a0f:7ec0:100:100:0:0:0:53
c.hu. 58905 AAAA 2001:738:2:2:0:0:0:53
d.hu. 68170 AAAA 2a00:e6a0:3:1014:0:0:53:99
e.hu. 74450 AAAA 2001:678:20:0:0:0:0:11
f.hu. 135907 AAAA 2001:678:c:0:0:0:0:1
p.hu. 68749 AAAA 2001:500:14:6146:ad:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0