smtp2-3.themailengine.com has no NS records.
NS records for this zone are defined at themailengine.com.
NS records for this zone are defined at themailengine.com.
Question and response
Question
dig smtp2-3.themailengine.com. NS
Answer
The response has no answer records.
Authority
themailengine.com. 300 SOA rush.easydns.com. zone.easydns.com. 1766118495 3600 600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0