GNOME Bugzilla – Bug 722284
Forwarding large mail attachment results in error
Last modified: 2015-03-10 09:59:06 UTC
Moving this from a downstream bug report: https://bugzilla.redhat.com/show_bug.cgi?id=1039308 When trying to forward many messages as one attachment (select messages in message list, then at the top Forward->As Attachment), results in an error: 'The reported error was "Invalid MIME content.".' The downstream bug report also contains a video demonstrating the issue, same as one test message. The view shows that the forwarded messages created 2.1MB attachment in size.
I tried to reproduce this with a 2010 Exchange server, and while I can reproduce it with your message, I cannot reproduce it with a message I created myself, where I have selected more than 200 simple messages (usually plain text or HTML messages). I would expect this being about particular message in the list, thus I tried to figure out which it is, by removing messages from bottom, but then I reached a state where the messages were send-able, in smaller chunks. And it confused me, because I can send significantly larger attachments without any issue. I checked how evolution-ews sends the messages, and it saves the message the same as in Outbox, thus the error is about some failure on the server side, when it was parsing the encoded messages. I tried also in OWA, but it attaches the message as a file, not as attached messages, which makes the difference.
I search the Net a bit and found [1] which suggests that the issue is with the server, if refuses to read certain attachments when they have some encoding. It seems to me that they do not interpret correctly (or maybe ignore) some Content-Transfer-Encoding values for attachments. Evolution-ews would be able to avoid that, by re-encode attachments, but that would not work in general, because for something like signed parts the re-encode would break the signature. Thus I'd blame the Exchange server. [1] http://msgroups.net/microsoft.public.mac.office.entourage/mail-sending-fails-on-e/56939