thumbtribe-jhb.thusadns.com has no NS records.
NS records for this zone are defined at thusadns.com.
NS records for this zone are defined at thusadns.com.
Question and response
Question
dig thumbtribe-jhb.thusadns.com. NS
Answer
The response has no answer records.
Authority
thusadns.com. 3601 SOA dns1.registrar-servers.com. hostmaster.registrar-servers.com. 1774039759 43200 3600 604800 3601
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0