Undelivered Mail Returned to Sender Error to Valid Email Addresses

[ahessini]

I have been continually receiving undelivered mail error messages after sending emails to valid addresses. Pasted below is the error message that I received. Any assistance on the root cause of this issue would be appreciated. Thank you.


"This is the mail system at host ns9.domainemailserver.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<[email protected]>: host
    za-smtp-inbound-2.mimecast.co.za[41.74.197.210] said: 550 csi.mimecast.org
    Poor Reputation Sender. - https://community.mimecast.com/docs/DOC-1369#550
    [YzlqdVrTPxCm77FGKLpF_Q.za34] (in reply to RCPT TO command)
Reporting-MTA: dns; ns9.domainemailserver.com
X-Postfix-Queue-ID: 7605A9000C1
X-Postfix-Sender: rfc822; [email protected]
Arrival-Date: Thu, 18 Jun 2020 23:45:08 +0200 (CEST)

Final-Recipient: rfc822; [email protected]
Original-Recipient: rfc822;[email protected]
Action: failed
Status: 5.0.0
Remote-MTA: dns; za-smtp-inbound-2.mimecast.co.za
Diagnostic-Code: smtp; 550 csi.mimecast.org Poor Reputation Sender. -
    https://community.mimecast.com/docs/DOC-1369#550
    [YzlqdVrTPxCm77FGKLpF_Q.za34]
Return-Path: <[email protected]>
Received: from localhost (localhost [127.0.0.1])
    by ns9.domainemailserver.com (Postfix) with ESMTP id 7605A9000C1
    for <[email protected]>; Thu, 18 Jun 2020 23:45:08 +0200 (CEST)
X-Virus-Scanned: Debian amavisd-new at ns9.domainemailserver.com
Received: from ns9.domainemailserver.com ([195.154.33.47])
    by localhost (ns9.domainemailserver.com [127.0.0.1]) (amavisd-new, port 10024)
    with ESMTP id uSMTyswDLg2U for <[email protected]>;
    Thu, 18 Jun 2020 23:44:56 +0200 (CEST)
Received: from pjudbenin.org (localhost [127.0.0.1])
    by ns9.domainemailserver.com (Postfix) with ESMTP id ADA189000C0
    for <[email protected]>; Thu, 18 Jun 2020 23:44:55 +0200 (CEST)
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="=_df9722e1c262f86b3f19021ba3a8e47e"
Date: Thu, 18 Jun 2020 16:44:55 -0500
From: [email protected]
To: [email protected]
Subject: Fwd: Demande de Financement de PJUD
In-Reply-To: <[email protected]>
References: <[email protected]>
<[email protected]>
Message-ID: <[email protected]>
X-Sender: [email protected]
User-Agent: Roundcube Webmail/1.3.8"

[SKaero]

The problem is at the top of the email "Poor Reputation Sender" that basically means that your mail server is on a spam blacklist so there server is rejecting your email.

[ahessini]

Oh I was under the impression this was referring to their address. Is there a way to remedy this or will I simply need to contact the respective receiver another way to get my address removed from their spam list?
Thank you for the clarification.

[SKaero]

You'll most likely need to contact them another way, I don't know how to you would get off the mimecast blacklist.

[ahessini]

Sounds good I will do so. Thank you for the reply.