Apex domains cannot have CNAME records.
Question and response
Question
dig SOVROSS.RU. NS
Answer
SOVROSS.RU. 5 NS ns2.rsnx.RU.
SOVROSS.RU. 5 NS ns1.rsnx.RU.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0