forum.successinet.com has no NS records.
NS records for this zone are defined at successinet.com.
NS records for this zone are defined at successinet.com.
Question and response
Question
dig forum.successinet.com. NS
Answer
The response has no answer records.
Authority
successinet.com. 3600 SOA ns1.successinet.com. hostmaster.successinet.com. 2018042516 10800 3600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0