Bjoern Franke via Mailman-users writes:
I was wondering about example.com,
Ah, OK. To my eye it looked like *you* redacted information about your domain by using that special domain. But no, that format is standard in our artificial DSNs. See OutgoingRunner._fake_dsn() in mailman/src/mailman/runners/outgoing.py.
I don't yet fully understand the internal bounce processing workflow, but it looks like that message is not supposed to go to the MTA. Did you get it out of the runner's queue? Or did it end up in a regular mailbox? I don't understand how the latter can happen.
My impression was (without looking into the logs) that the mails got classified as spam and rejected because the were sent from example.com.
*This* message was sent "From" example.com, but it reports on a *different* message that was classed as spam and rejected. It's still not clear to me whether this message was actually bounced by an MTA, ended up in some legitimate mailbox, or you fetched it from the runner's queue.
The other message seems to have actually been spam. Everybody is rejecting it. It's hard to say without knowing a lot more about your software and configuration, but I don't see anything that looks off here.