Apex domains cannot have CNAME records.
Question and response
Question
dig nwlk.ru. NS
Answer
nwlk.ru. 5 NS ns.nalitch.spb.ru.
nwlk.ru. 5 NS ns.pulkov.spb.ru.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0