Apex domains cannot have CNAME records.
Question and response
Question
dig cdn.GBlNeT.ru. NS
Answer
cdn.GBlNeT.ru. 5 NS ns1.cdn.GBlNeT.ru.
cdn.GBlNeT.ru. 5 NS ns.GBlNeT.ru.
Authority
The response has no authority records.
Additional
ns.GbLNET.ru. 5 A 95.140.80.1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0