Because of a severe mailbomb I experienced the last few days, it was necessary to block incoming mail from several hundred .au domains with improperly configured mail servers that bounce mail to non-existent addresses by storing the e-mail, looking up the incoming address, and sending it back, rather than refusing it up front and at the same time don’t bother to check SPF, DMARC, or DKIM records to make sure the address they are bouncing too isn’t forged.
So if you are expecting mail from Australia and do not receive it, generate a ticket at https://www.eskimo.com/support/osTicket/ and let me know and I’ll checked to see if it’s on the blocked list. This ban is not intended to be permanent, just until the person initiating the mailbomb gets bored and moves on.