mail1.informz.net has no NS records.
NS records for this zone are defined at informz.net.
NS records for this zone are defined at informz.net.
Question and response
Question
dig mail1.informz.net. NS
Answer
The response has no answer records.
Authority
informz.net. 900 SOA ns-15.awsdns-01.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0