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