fast.ddns.com.au has no MX records.
Question and response
Question
dig fast.ddns.com.au. MX
Answer
The response has no answer records.
Authority
ddns.com.au. 900 SOA dns4.quick.net.au. domains.ddns.com.au. 2026021902 10800 900 1209600 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0