Apex domains cannot have CNAME records.
Question and response
Question
dig simdev.ru. NS
Answer
simdev.ru. 5 NS ns1.simdev.ru.
simdev.ru. 5 NS ns2.simdev.ru.
Authority
The response has no authority records.
Additional
ns1.simdev.ru. 5 A 87.76.8.75
ns2.simdev.ru. 5 A 87.76.8.76
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0