mail.OCSWORK.RU has no CNAME records.
Question and response
Question
dig mail.OCSWORK.RU. NS
Answer
The response has no answer records.
Authority
ocswork.ru. 669 SOA ns01.1cloud.ru. support.1cloud.ru. 2026030501 1800 900 604800 1200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0