dev-back.GBlNET.net has no CNAME records.
Question and response
Question
dig dev-back.GBlNET.net. NS
Answer
The response has no answer records.
Authority
GBlNET.net. 6673 SOA ns.GBlNET.net. vvv.GBlNET.net. 2026022701 10800 1200 1209600 259200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0