us.mail.workfront.com has no NS records.
NS records for this zone are defined at mail.workfront.com.
NS records for this zone are defined at mail.workfront.com.
Question and response
Question
dig us.mail.workfront.com. NS
Answer
The response has no answer records.
Authority
mail.workfront.com. 900 SOA ns-340.awsdns-42.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0