dev2.mailendo.com has no NS records.
NS records for this zone are defined at mailendo.com.
NS records for this zone are defined at mailendo.com.
Question and response
Question
dig dev2.mailendo.com. NS
Answer
The response has no answer records.
Authority
mailendo.com. 900 SOA ns-318.awsdns-39.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0