Apex domains cannot have CNAME records.
Question and response
Question
dig corp.mchost.RU. NS
Answer
corp.mchost.RU. 5 NS dns1.mchost.RU.
corp.mchost.RU. 5 NS dns2.mchost.com.
Authority
The response has no authority records.
Additional
dns2.mchost.com. 5 A 46.254.23.53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0