Apex domains cannot have CNAME records.
Question and response
Question
dig GbLnet.RU. NS
Answer
GbLnet.RU. 5 NS ns.GbLnet.RU.
GbLnet.RU. 5 NS ns2.GbLnet.RU.
Authority
The response has no authority records.
Additional
ns.gblnet.RU. 5 A 95.140.80.1
ns2.gblnet.ru. 5 A 95.140.83.1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0