Yes, When I first received the notice I considered the possibility that either the client or the server was compromised. I started by changing the client system to ensure that was not the issue - it is not, same error happens no matter the client or system sent from via Exim. I then thoroughly inspected the exam server and the MTA. Ultimately, because it was not revealing anything, I rebuilt the system (I had other reasons to do that partially due to failing hardware). The problem has persisted.
Yahoo has no answer and is unwilling to provide more response than they do not think there is an issue. Unless someone has a better way to contact them than via their forums and their mail server debugging email, I do not know how to get their attention. It does appear that my MTA is not the only one having an issue on their forums, but nobody seems to have found a solution.
No other listserv or service provider returns this error. When sending to Yahoo Mail - to an individual, there is also no issue. I have thoroughly inspected my outgoing messages for malicious content as well as the headers, but it has literally revealed nothing that should be an issue. That said the only difference between messages sent directly via the mail server and messages from a client appear to be the headers. I suppose I could set the server to not modify or set any headers and see if a message goes through....
.
> On Mar 24, 2017, at 09:31, Jeremy Harris <jgh@???> wrote:
>
>> On 24/03/17 07:30, Jay Gairson via Exim-users wrote:
>> Any tips on next steps to debug this issue and remedy it?
>
> Get further details from them, unfortunately.
>
> Try asking on the "mailop" list:
> mailto:mailop-request@mailop.org?subject=subscribe
>
> --
> Cheers,
> Jeremy
>
>
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