Apex domains cannot have CNAME records.
Question and response
Question
dig USERECHO.RU. NS
Answer
USERECHO.RU. 5 NS ns.us4.stamul.com.
USERECHO.RU. 5 NS ns.eu2.stamul.com.
USERECHO.RU. 5 NS ns.ru1.USERECHO.RU.
Authority
The response has no authority records.
Additional
ns.eu2.stamul.com. 5 A 195.201.170.200
ns.ru1.USERECHO.RU. 5 A 77.223.108.162
ns.us4.stamul.com. 5 A 40.160.21.214
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0