exchange 2007 error

[bsl19738]

I am getting the error below. I have looked at the Microsoft KB article on how to fix I am not understanding how I can get this cleared up. We are able to receive all emails but not able to send to external email addresses. Can anyone help me try and fix this?

Delivery has failed to these recipients or distribution lists:

'Brian Lichtig'
An error occurred while trying to deliver this message to the recipient's e-mail address. Microsoft Exchange will not try to redeliver this message for you. Please try resending this message, or provide the following diagnostic text to your system administrator.

The following organization rejected your message: mta294.mail.re4.yahoo.com.

  _____  

Sent by Microsoft Exchange Server 2007







Diagnostic information for administrators:

Generating server: exchange2007.northernpharmacy.com

bsl19738@yahoo.com
mta294.mail.re4.yahoo.com #553 Mail from blichtig@northernpharmacy.com not allowed - 5.7.1 [BL23] Connections not accepted from IP addresses on Spamhaus XBL; see

http://postmaster.yahoo.com/550-bl23.html

[550] ##

Original message headers:

Received: from exchange2007.northernpharmacy.com ([192.168.1.171]) by
exchange2007.northernpharmacy.com ([192.168.1.171]) with mapi; Tue, 30 Jun
2009 12:11:18 -0400
From: brian Lichtig <blichtig@northernpharmacy.com>
To: 'Brian Lichtig' <bsl19738@yahoo.com>
Disposition-Notification-To: brian Lichtig <blichtig@northernpharmacy.com>
Date: Tue, 30 Jun 2009 12:11:17 -0400
Subject: RE: test
Thread-Topic: test
Thread-Index: Acn5nWFgGNL05Q7OTyGRG2BnvOyX7AAAALNg
Message-ID: <BEFB13462C038048BD1C19F1A
E0936FE1C8060C62F@exchange2007.northernpharmacy.com>
References: <269615.25767.qm@web65710.mail.ac4.yahoo.com>
In-Reply-To: <269615.25767.qm@web65710.mail.ac4.yahoo.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
acceptlanguage: en-US
Content-Type: multipart/alternative;
boundary="_000_BEFB13462C038048BD1C19F1AE0936FE1C8060C62Fexchange2007n_"
MIME-Version: 1.0

 

[58sniper]

It says why right in the message

Connections not accepted from IP addresses on Spamhaus XBL; see

http://postmaster.yahoo.com/550-bl23.html

Go to that URL and start reading.

Pat Richard MVP
Plan for performance, and capacity takes care of itself. Plan for capacity, and suffer poor performance.

http://www.ucblogs.net/blogs/exchange/