Apex domains cannot have CNAME records.
Question and response
Question
dig x5-tech.ru. NS
Answer
x5-tech.ru. 1 NS ns8-l2.nic.ru.
x5-tech.ru. 1 NS ns2.x5.ru.
x5-tech.ru. 1 NS ns1.x5.ru.
x5-tech.ru. 1 NS ns4-l2.nic.ru.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0