I am new to zimbra. Users at our domain.com complain that when they send mails to people it is either returned and marked as spam or it ends up in the recipients junk folder. Here is a recent report of Undelivered mail. (actual names of sender and recipient have been changed to protect identity)

The mail system

<recipeint@recipeintdomain.com>: host mail.recipientdomain.com[] said: 554
Transaction Failed Spam Message not queued. (in reply to end of DATA
Reporting-MTA: dns; mail.ourdomain.com X-Postfix-Queue-ID: 6E1938760F99 X-Postfix-Sender: rfc822; sender@ourdomain.com Arrival-Date: Thu, 6 Sep 2012 07:29:34 -0500 (CDT) Final-Recipient: rfc822; recipient@recipeintdomain.com Original-Recipient: rfc822;recipient@recipeintdomain.com Action: failed Status: 5.0.0 Remote-MTA: dns; mail.recipeintdomain.com Diagnostic-Code: smtp; 554 Transaction Failed Spam Message not queued.

Some of the mails we send, this is the report that is returned.

Please, does anyone has any idea as to what the problem is and how we can bypass this problem of our mails being marked as spam.

Thank you