mailin.cloud.coop has no NS records.
NS records for this zone are defined at cloud.coop.
NS records for this zone are defined at cloud.coop.
Question and response
Question
dig mailin.cloud.coop. NS
Answer
The response has no answer records.
Authority
cloud.coop. 60 SOA ns-1528.awsdns-63.org. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0