cache.cdn.gblnet.ru has no CNAME records.
Question and response
Question
dig cache.cdn.gblnet.ru. NS
Answer
The response has no answer records.
Authority
cdn.GbLNET.ru. 9458 SOA localhost. root.localhost. 2026020601 604800 86400 2419200 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0