Apex domains cannot have CNAME records.
Question and response
Question
dig essote.fi. NS
Answer
essote.fi. 5 NS dns1.louhi.net.
essote.fi. 5 NS dns2.louhi.net.
essote.fi. 5 NS dns3.louhi.fi.
Authority
The response has no authority records.
Additional
dns1.louhi.net. 5 A 77.240.18.27
dns2.louhi.net. 5 A 77.240.22.185
dns3.louhi.fi. 5 A 79.171.225.17
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0