mantlet.messagesystems.com has no NS records.
NS records for this zone are defined at messagesystems.com.
NS records for this zone are defined at messagesystems.com.
Question and response
Question
dig mantlet.messagesystems.com. NS
Answer
The response has no answer records.
Authority
messagesystems.com. 900 SOA ns-1755.awsdns-27.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0