Apex domains cannot have CNAME records.
Question and response
Question
dig sibmediafon.RU. NS
Answer
sibmediafon.ru. 5 NS ns.sibmediafon.ru.
sibmediafon.ru. 5 NS ns1.sibmediafon.ru.
Authority
The response has no authority records.
Additional
ns.sibmediafon.RU. 5 A 91.211.56.221
ns1.sibmediafon.RU. 5 A 91.211.56.210
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0