mw80.mail2world.com has no NS records.
NS records for this zone are defined at mail2world.com.
NS records for this zone are defined at mail2world.com.
Question and response
Question
dig mw80.mail2world.com. NS
Answer
The response has no answer records.
Authority
mail2world.com. 300 SOA mwdns10vmoc.mail2world.com. dns_admin.mail2world.net. 2016043392 3600 300 1814400 300
Additional
. 0 OPT ; payload 4000, xrcode 0, version 0, flags 0