Apex domains cannot have CNAME records.
Question and response
Question
dig FONCOR.RU. NS
Answer
FONCOR.RU. 1 NS ns1.edgedns.ru.
FONCOR.RU. 1 NS ns2.edgedns.world.
Authority
The response has no authority records.
Additional
ns1.edgedns.ru. 1 A 5.188.176.176
ns2.edgedns.world. 1 A 5.101.71.71
ns1.edgedns.ru. 1 AAAA 2a11:27c0:1010:0:0:0:0:1176
ns2.edgedns.world. 1 AAAA 2a13:1ec0:1000:0:0:0:0:1071
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0