Apex domains cannot have CNAME records.
Question and response
Question
dig OCSWORK.RU. NS
Answer
OCSWORK.RU. 5 NS ns01.1cloud.RU.
OCSWORK.RU. 5 NS ns02.1cloud.RU.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0