Apex domains cannot have CNAME records.
Question and response
Question
dig tld.ee. NS
Answer
tld.ee. 5 NS c.tld.ee.
tld.ee. 5 NS ans1.aso.ee.
tld.ee. 5 NS b.tld.ee.
tld.ee. 5 NS e.tld.ee.
tld.ee. 5 NS x.tld.ee.
Authority
The response has no authority records.
Additional
b.tld.ee. 5 A 194.146.106.110
c.tld.ee. 5 A 195.43.86.90
e.tld.ee. 5 A 204.61.216.36
x.tld.ee. 5 A 195.43.87.186
ans1.aso.ee. 5 A 195.80.103.202
b.tld.ee. 5 AAAA 2001:67c:1010:28:0:0:0:53
e.tld.ee. 5 AAAA 2001:678:94:53:0:0:0:53
x.tld.ee. 5 AAAA 2a00:c3a0:53:58:0:0:0:53
ans1.aso.ee. 5 AAAA 2a02:88:0:417:195:80:103:202
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0