I'm not sure the usage of "ToSenderFolder" in "mailetcontainer.conf" is correct.
Here is the code: <mailet match="RecipientIsLocal" class="ToSenderFolder"> <folder>Sent</folder> <consume>false</consume> </mailet> I think that matcher should match known senders, not any local recipient. I'm not sure what is the exact matcher for that, maybe "SMTPAuthSuccessful" ?