troubleshooting Question

Email Rejected by one system with #5.0.0 smtp;555 error

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PMIMISFlag for United States of America asked on
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6 Comments1 Solution1883 ViewsLast Modified:
Hello experts!

I have an email sending problem and I am hoping one of you will have some insight that can help me solve this problem

My company has a new client, but all emails from us to them are rejected with a 555 error. My research so far suggests this means a protocol mismatch, but I don't really know what that means.

This happens for emails sent to this customer from any mailbox in our organization. We do not have this problem when sending to any other people or companies and our system has been up for years.

Email sent from my user's personal email account and from my Gmail account is received successfully.

I tried creating a special send connector just for this domain that Forces Helo instead of Ehlo, but that did not fix anything.

Our email servers are all Exchange 2010 with Service Pack 2 and Update Rollup 6. Mail failures occur whether we send with Outlook 2010 client or OWA.

Bounce message follows:

Sent: Friday, August 30, 2013 9:10 AM
To: IT Admin
Subject: Undeliverable: RE: Test Email

Delivery has failed to these recipients or groups:
A problem occurred during the delivery of this message to this e-mail address. Try sending this message again. If the problem continues, please contact your helpdesk.

The following organization rejected your message:

Diagnostic information for administrators:

Generating server: #< #5.0.0 smtp;555 Unsupported option: AUTH=<>> #SMTP#

Original message headers:

Received: from ( by ( with Microsoft SMTP Server id; Fri, 30 Aug 2013 16:09:50 +0000
Received: from mail112-tx2 (localhost [])      by (Postfix) with ESMTP id 5E1B73A0171      for
 <>; Fri, 30 Aug 2013 16:09:50 +0000 (UTC)
X-Forefront-Antispam-Report: CIP:ww.xx.yy.zz;KIP:(null);UIP:(null);IPV:NLI;;RD:none;EFVD:NLI
X-SpamScore: -1
X-BigFish: VPS-1(z569dhz9371Ic85fhdbeeh55dIzz208ch1ee6h1fdah2073h1202h1e76h1d2ah1fc6hzz1d7338h1de098h1b1984h6d524h17326ah18c673h186068h1954cbh18602eh8275bh1bc7b9h8275dh1de097hz31h2a8h839h8e2h8e3hd25hf0ah1288h12a5h12bdh137ah1441h14ddh1504h1537h153bh15d0h162dh1631h1758h18e1h1946h19b5h1a24h1a82h1ad9h1b0ah1b2fh1bceh1fb3h1d0ch1d2eh1d3fh1dc1h1dfeh1dffh1e1dh1fe8h1ff5hbe9i1155h)
Received-SPF: softfail (mail112-tx2: transitioning domain of does not designate ww.xx.yy.zz as permitted sender) client-ip=ww.xx.yy.zz;; ; ;
Received: from mail112-tx2 (localhost.localdomain []) by mail112-tx2
 (MessageSwitch) id 1377878934621385_7997; Fri, 30 Aug 2013 16:08:54 +0000
Received: from (unknown [])      by (Postfix) with ESMTP id 846A32E0053      for
 <>; Fri, 30 Aug 2013 16:08:54 +0000 (UTC)
Received: from (ww.xx.yy.zz) by ( with Microsoft SMTP Server (TLS) id; Fri, 30 Aug 2013 16:08:52 +0000
Received: from MailServer.Company.corp ([fe80::f515:b53:b437:cb07]) by
 MailServer.Company.corp ([fe80::f515:b53:b437:cb07%14]) with mapi id
 14.02.0342.003; Sat, 31 Aug 2013 00:08:50 +0800
From: IT Admin <>
To: "" <>
Subject: RE: Test Email
Thread-Topic: Test Email
Thread-Index: Ac6lkX32hYETuTz+SWiivEWUmUqrQgACbAhw
Date: Fri, 30 Aug 2013 16:08:49 +0000
Message-ID: <9E1A6C20647B694EBA6C500F52376EBD1D8D77A0@MailServer.Company.corp>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach: yes
x-originating-ip: []
Content-Type: multipart/related;
MIME-Version: 1.0
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