Apex domains cannot have CNAME records.
Question and response
Question
dig sovross.ru. NS
Answer
sovross.ru. 3 NS ns2.rsnx.ru.
sovross.ru. 3 NS ns1.rsnx.ru.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0