Apex domains cannot have CNAME records.
Question and response
Question
dig silinet.ru. NS
Answer
silinet.ru. 5 NS ns1.fiord.ru.
silinet.ru. 5 NS ns3.fiord.ru.
silinet.ru. 5 NS ns2.fiord.ru.
Authority
The response has no authority records.
Additional
ns1.fiord.ru. 5 A 62.140.230.9
ns3.fiord.ru. 5 A 62.140.239.1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0