Apex domains cannot have CNAME records.
Question and response
Question
dig sn.ru. NS
Answer
sn.ru. 5 NS ns5.salenames.ru.
sn.ru. 5 NS ns6.salenames.ru.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0