ns1.amzndns.com has no NS records.
NS records for this zone are defined at amzndns.com.
NS records for this zone are defined at amzndns.com.
Question and response
Question
dig ns1.amzndns.com. NS
Answer
The response has no answer records.
Authority
amzndns.com. 907 SOA g-ns1.amzndns.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 907
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0