We're testing Zimbra for possible migration from another solution (or as a companion to); but we keep getting 554 errors like this:
554 Transaction Failed: Command "FROM" field differs from data "FROM" field.
The mail is first passed through a MailFoundry appliance for content filtering. Spam/virus filtering is disabled in Zimbra. For the domain, I've set inbound host field to that of the MailFoundry appliace (I've also tried leaving it blank).
Where did I go wrong?