Apex domains cannot have CNAME records.
Question and response
Question
dig plpod.ru. NS
Answer
plpod.ru. 5 NS ns.pledpodushkin.ru.
plpod.ru. 5 NS ns1.pledpodushkin.ru.
Authority
The response has no authority records.
Additional
ns.PLEDPODUSHKIN.RU. 5 A 94.250.252.253
ns1.PLEDPODUSHKIN.RU. 5 A 176.62.179.247
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0