Apex domains cannot have CNAME records.
Question and response
Question
dig TATTELECOM.RU. NS
Answer
tattelecom.RU. 1 NS ns.tattelecom.ru.
tattelecom.RU. 1 NS ns2.tattelecom.ru.
Authority
The response has no authority records.
Additional
ns.tattelecom.RU. 1 A 217.23.176.1
ns2.tattelecom.RU. 1 A 217.23.177.249
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0