Last Thursday (25 Aug) a sender from setonvilla.org.au (office365 mail) sent me an email and received an "SPF validation error" with a bounce back email. He has been unable to send me emails since.
1. This was working fine up until that email.
2. Circular emails to others (including my email) are received by me when they 'reply all', so the email address is correct.
3. The sender can receive my emails if I send then from TPG.
Can someone shed some light as to what is going on here?
M
