This is the correct tracker for Mailman 2.1 issues. The headers at https://bugs.launchpad.net/mailman/+bug/1787690/comments/2 are only the message headers and only say that the message's Conternt-Type: is multipart/mixed. If I send a message from Gmail on my android phone it has the following MIME structure. multipart/alternative text/plain the plain text alternative text/html the html alternative I suspect the message you are looking at from the list has structure multipart/mixed multipart/alternative text/plain the plain text alternative text/html the html alternative text/plain the list footer I can download the https://bugs.launchpad.net/mailman/+bug/1787690/+attachment/5181125/+files/S... attachment, but I can't open it with anything that renders it properly. 'file' tells me "Composite Document File V2 Document, Cannot read section info". Note that you can't use wildcards in pass_mime_types, but you can specify a main type without a subtype. I.e., this multipart text in pass_mime_types will accept any text/* elemental parts within any multipart/* parts. Also note that Content filtering -> filter_action controls what is done with a message from which content filtering removes everything and there should always be a Message discarded or Message rejected message in the vette log in any case. Is there anything in Mailman's error log? If you have problem posting a raw message, just send a message from your android gmail app with Subject: Bug 1787690 to mark@msapiro.net. -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1787690 Title: Mailman rejects multipart content from Gmail/android To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1787690/+subscriptions