d.nic.icu has no NS records.
NS records for this zone are defined at nic.icu.
NS records for this zone are defined at nic.icu.
Question and response
Question
dig d.nic.icu. NS
Answer
The response has no answer records.
Authority
nic.icu. 3600 SOA ns0.centralnic-dns.com. hostmaster.centralnic-dns.com. 1773328094 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0