_netblocks2.gsi-network.com has no CNAME records.
Question and response
Question
dig _netblocks2.gsi-network.com. NS
Answer
The response has no answer records.
Authority
gsi-network.com. 261 SOA dns.gsi-network.com. dns.gsi-network.com. 2026030702 300 540 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0