When users try to send a calendar appointment outside of the domain they recieve the following error after recieving the delayed error(s). The following recipient(s) cannot be reached: Externalemail on 01/15/2011 12:55 PM Could not deliver the message in the time limit specified. Please retry or contact your administrator. <localserver.domain #4.4.7> We are only seeing this for a few users and so far it is only reported on appointments sent. We are currently on Exchange 2003 servers. We run all of our outbound messages through a Barracuda firewall and the messages are not making it to the Barracuda either. Barracuda is not seeing any issues preventing these messages from reaching Barracuda from their side.

I recommend this site to review the, http://geekswithblogs.net/BWCA/archive/2009/06/09/outlook-2007-ical-issue-with-external-recipients---4.4.7-ndr.aspx

Hi Numeric Code: 4.4.7 Possible Cause: The message in the queue has expired. The sending server tried to relay or deliver the message, but the action was not completed before the message expiration time occurred. This NDR may also indicate that a message header limit has been reached on a remote server or that some other protocol timeout occurred during communication with the remote server. Troubleshooting: This code typically indicates an issue on the receiving server. Verify the validity of the recipient address, and verify that the receiving server is configured to receive messages correctly. You may have to reduce the number of recipients in the header of the message for the host that you are receiving this NDR from. If you resend the message, it is placed in the queue again. If the receiving server is on line, the message is delivered. http://support.microsoft.com/kb/284204Jonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | Blog: http://www.testlabs.se/blog | Follow me on twitter: jonand82

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