We’ve had the following response from AOL to our query about incoming email from AOL addresses being bounced back to the senders:
We had few issues with our Outbound IP’s timing out with few mail servers last week. Are you still seeing reports of our users not able to connect to your servers? Please send me the headers and I can check the logs at our end. With regards to Spam Flag Yes- we are seeing lots of AOL accounts being compromised forcing us to send mails through our aberrant IP’s. These mails might be rejected at our end too if we suspect compromise but do issue a bounce message.
This would seem to indicate that AOL has solved the issue of legitimate email sent to NinerNet clients being returned as undeliverable. We’ve had no reports of incoming email from AOL senders being bounced for over a week now, so we’ll consider this matter closed.