ns.kakaocorp.com has no NS records.
NS records for this zone are defined at kakaocorp.com.
NS records for this zone are defined at kakaocorp.com.
Question and response
Question
dig ns.kakaocorp.com. NS
Answer
The response has no answer records.
Authority
kakaocorp.com. 300 SOA ns.kakaocorp.com. root.kakaocorp.com. 1667984524 1800 600 2419200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0