_netblocks.net.hostasaurus.com has no CNAME records.
Question and response
Question
dig _netblocks.net.hostasaurus.com. NS
Answer
The response has no answer records.
Authority
hostasaurus.com. 938 SOA ns3.hostasaurus.com. hostmaster.hostasaurus.com. 1769190313 16384 2048 1048576 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0