mx3.recruitmail.com has no NS records.
NS records for this zone are defined at recruitmail.com.
NS records for this zone are defined at recruitmail.com.
Question and response
Question
dig mx3.recruitmail.com. NS
Answer
The response has no answer records.
Authority
recruitmail.com. 900 SOA ns-495.awsdns-61.com. awsdns-hostmaster.amazon.com. 2018070904 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0