Problems routing faxes through email

I have a Windows Server 2008 fax server that is giving me some problems when trying to route inbound faxes via email.

Sometimes it will work, and then eventually an inbound fax will get stuck with a status of "Retrying Routing" when viewing it in the Windows XP Fax Console on the client. When this happens, the fax server will record the following 2 events in the Application event log:

Event ID: 32083   Source: Microsoft Fax   Task Category: Inbound   User: N/A

Unable to route fax C:\ProgramData\Microsoft\Windows NT\MSFax\Queue\1C9889BC4B822.tif to the requested e-mail address.

 The following error occurred: 0x80040211
 This error code indicates the cause of the error.

 Check the SMTP server configuration, and correct any anomalies.

Event ID: 32089   Source: Microsoft Fax   Task Category: Inbound   User: N/A

The Fax Service failed to execute a specific routing method. The service will retry to route the fax according to the retries configuration. If the retries fail, verify routing method configuration.
 Job ID: 0x0401c9889bc4b822.
 Received on Device: 'Conexant D850 PCI V.92 Modem'
 Sent from: '123123456'
 Received file name: 'C:\ProgramData\Microsoft\Windows NT\MSFax\Queue\1C9889BC4B822.tif'.
 Routing extension name: 'Microsoft Routing Extension'
 Routing method name: 'Route through e-mail'


Sometimes, the fax will eventually go through. Other times, it will fail completely. If it fails completely, the following event is logged in the Application event log and all faxes after this one will fail too.

Event ID: 32078   Source: Microsoft Fax   Task Category: Inbound   User: N/A

A successfully received fax was not routed automatically. You can find the fax in the Inbox/Incoming archive folder by its Job ID. Job ID: 0x0401c988900827e4. Received on Device: 'Conexant D850 PCI V.92 Modem' Sent from: '987-654-3210'


If I clear all the stuck faxes out of the "Incomming" folder of the fax console, then future faxes might come through successfully (by clear I mean delete them).

I followed the instructions from the following link to get an authenticated user set up instead of using anonymous, but that hasn't helped.

http://blogs.technet.com/sbs/archive/2007/04/02/inbound-fax-routing-may-fail-due-to-the-exchange-intelligent-message-filter-imf.aspx

Any help anyone has would be greatly appreciated as this is getting frustrating.

Thanks!