Hi all, we’ve noticed that outlook is returning 4xx for forwards with a valid DKIM because there is a duplicate signed header. Usually a Mime-Version header.
Microsoft now verifies the mime structure before DKIM so these fail DMARC despite a valid DKIM. We’re seeing this with pretty large senders like TikTok, Volkswagen, and many others. How do other people deal with this? “Sender problem”? Regards Cor _______________________________________________ mailop mailing list -- [email protected] To unsubscribe send an email to [email protected]
