I also just tested it with Content-Type, same problem. So likely also other headers.
But these headers have to actually be duplicated. Im guessing mailop itself doesn’t do that, it only over signs. Many senders do add duplicate headers, and we mostly see this with Mime-Version for some reason. My guess, MS first “fixes” the header to remove the duplicate, and then verifies the signature, which then obviously doesnt validate anymore. I’m inclined to say “sender problem”, but this is happening with some pretty large senders. cor _______________________________________________ mailop mailing list -- [email protected] To unsubscribe send an email to [email protected]
