spf.qsl.net.au has no MX records.
Question and response
Question
dig spf.qsl.net.au. MX
Answer
The response has no answer records.
Authority
qsl.net.au. 3600 SOA ns1.melbourneit.net. admin.melbourneit.net. 2025052702 86400 7200 3600000 172800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0