spf.postal.pdx.net.uk has no MX records.
Question and response
Question
dig spf.postal.pdx.net.uk. MX
Answer
The response has no answer records.
Authority
pdx.net.uk. 3600 SOA apollo.ns.pdxdns.net. dns.pdxnet.co.uk. 2026021604 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0