mail.silverpopuk.com has no NS records.
NS records for this zone are defined at silverpopuk.com.
NS records for this zone are defined at silverpopuk.com.
Question and response
Question
dig mail.silverpopuk.com. NS
Answer
The response has no answer records.
Authority
silverpopuk.com. 900 SOA ns1.acoustic-adm.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0