ns3.ncuk.net.uk has no MX records.
Question and response
Question
dig ns3.ncuk.net.uk. MX
Answer
The response has no answer records.
Authority
ncuk.net.uk. 3600 SOA ns0.ncuk.net. hostmaster.ncuk.com. 2019121801 7200 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0