Apex domains cannot have CNAME records.
Question and response
Question
dig ONYMA.RU. NS
Answer
onyma.ru. 5 NS ns.stacksoft.ru.
onyma.ru. 5 NS ns2.stacksoft.ru.
Authority
The response has no authority records.
Additional
ns.stacksoft.RU. 5 A 217.73.199.113
ns2.stacksoft.ru. 5 A 213.152.131.125
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0