Apex domains cannot have CNAME records.
Question and response
Question
dig UPLINK-OLEKMINSK.RU. NS
Answer
uplink-olekminsk.ru. 4 NS ns2.UPLINK-OLEKMINSK.RU.
uplink-olekminsk.ru. 4 NS ns1.UPLINK-OLEKMINSK.RU.
Authority
The response has no authority records.
Additional
ns1.uplink-olekminsk.ru. 4 A 134.19.151.186
ns2.uplink-olekminsk.ru. 4 A 134.19.151.187
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0