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