mx240.umbler.co.uk has no NS records.
NS records for this zone are defined at umbler.co.uk.
NS records for this zone are defined at umbler.co.uk.
Question and response
Question
dig mx240.umbler.co.uk. NS
Answer
The response has no answer records.
Authority
umbler.co.uk. 900 SOA ns-1673.awsdns-17.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0