mail.cyberville.com.sg has no NS records.
NS records for this zone are defined at cyberville.com.sg.
NS records for this zone are defined at cyberville.com.sg.
Question and response
Question
dig mail.cyberville.com.sg. NS
Answer
The response has no answer records.
Authority
cyberville.com.sg. 1800 SOA eoin.ns.cloudflare.com. dns.cloudflare.com. 2399376528 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0