one.one.one.one has no NS records.
NS records for this zone are defined at one.one.one.
NS records for this zone are defined at one.one.one.
Question and response
Question
dig one.one.one.one. NS
Answer
The response has no answer records.
Authority
one.one.one. 1800 SOA dorthy.ns.cloudflare.com. dns.cloudflare.com. 2398800047 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0