Apex domains cannot have CNAME records.
Question and response
Question
dig simdev.RU. NS
Answer
SIMDEV.RU. 1 NS ns1.SIMDEV.RU.
SIMDEV.RU. 1 NS ns2.SIMDEV.RU.
Authority
The response has no authority records.
Additional
ns1.SIMDEV.RU. 1 A 87.76.8.75
ns2.SIMDEV.RU. 1 A 87.76.8.76
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0