Apex domains cannot have CNAME records.
Question and response
Question
dig netexpert.RU. NS
Answer
netexpert.RU. 2 NS ns.sknt.ru.
netexpert.RU. 2 NS skynet.ns.netexpert.ru.
Authority
The response has no authority records.
Additional
ns.SKNT.RU. 2 A 93.100.1.66
skynet.ns.netexpert.RU. 2 A 94.19.255.12
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0