Apex domains cannot have CNAME records.
Question and response
Question
dig infonet.ee. NS
Answer
infonet.ee. 4 NS ns2.infonet.ee.
infonet.ee. 4 NS ns.infonet.ee.
Authority
The response has no authority records.
Additional
ns.infonet.ee. 4 A 212.7.0.1
ns2.infonet.ee. 4 A 212.7.9.34
ns.infonet.ee. 4 AAAA 2001:1b28:1:1:0:0:0:1
ns2.infonet.ee. 4 AAAA 2001:1b28:1:7:0:0:0:34
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0