Apex domains cannot have CNAME records.
Question and response
Question
dig bizml.ru. NS
Answer
bizml.ru. 5 NS bizns3.mail.ru.
bizml.ru. 5 NS bizns4.mail.ru.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0