Could not deliver to the following recipient. Remote host said: 554 5.7.1

I had to start a new thread for this because, despite being logged in, the forum wouldn't let me add anything to the prior thread.

Here's the header from the failed Outlook message. This was sent subsequent to a test from web mail using the same mailbox which appears to have been received. 

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Received: from ARSENAL (c-24-16-135-166.hsd1.wa.comcast.net [24.16.135.166]) by mail.resmachina.com with SMTP;

   Thu, 16 May 2013 08:55:19 -0700

From: "Robert D. Pinkerton" <email@myaddress.com>

To: "myrecipient" <myrecipient@xyz.com>

Subject: Test #2

Date: Thu, 16 May 2013 08:55:10 -0700

Organization: Symantry Marketing LLC

Message-ID: <024d01ce524d$bf473f40$3dd5bdc0$@symantry.com>

MIME-Version: 1.0

Content-Type: multipart/related;

                boundary="----=_NextPart_000_024E_01CE5213.12E9C6D0"

X-Mailer: Microsoft Outlook 15.0

Thread-Index: Ac5STbUFwh3CITQgQ3WrWp85HyRUuA==

Content-Language: en-us

This is a multipart message in MIME format.

------=_NextPart_000_024E_01CE5213.12E9C6D0

Content-Type: multipart/alternative;

                boundary="----=_NextPart_001_024F_01CE5213.12E9C6D0"

------=_NextPart_001_024F_01CE5213.12E9C6D0

Content-Type: text/plain;

                charset="us-ascii"

Content-Transfer-Encoding: 7bit

Second test to see if my emails are getting through to you.

Bob

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Here's the header from the webmail that was delivered:

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Received: by mail.resmachina.com via HTTP;
	Thu, 16 May 2013 08:52:20 -0700
From: "Robert D. Pinkerton" 
To: 
Subject: Testing for Spam trap sending to Colleen
Date: Thu, 16 May 2013 08:52:20 -0700
Reply-To: bob@symantry.com
Message-ID: <4be908b3$4fc7ce66$2a0f5fbc$@com>
MIME-Version: 1.0
Content-Type: multipart/alternative;
	boundary="----=_NextPart_000_0001_32AAE06D.4EE07719"
X-Originating-IP: [24.16.135.166]

------------------------------------------------------------------------------------------------------------------------------------------------------

I didn't understand one part of your commentary regarding static IPs versus dynamic. I get the idea that you are looking to restrict people from running servers on a dynamic IP address. I'm not doing that. My server is in my ISPs data center in AZ. But, just adding the Comcast dynamic IP address to the mail header gets me blacklisted because you blacklisted this IP address yourselves. It's almost like you are trying to prevent behavior that is perfectly reasonable - sending an e-mail from a Comcast-connected PC through a remote corporate mail server.

Thanks for any assistance.