pdns3.qualityunit.com has no NS records.
NS records for this zone are defined at qualityunit.com.
NS records for this zone are defined at qualityunit.com.
Question and response
Question
dig pdns3.qualityunit.com. NS
Answer
The response has no answer records.
Authority
qualityunit.com. 900 SOA ns-538.awsdns-03.net. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0