Error message after an Exchange Server 2007 Service Pack 1 user replies to a message that has more than 300 recipients in Outlook Web Access (OWA): "Microsoft Exchange issued an unexpected response (500)"

Symptoms

When an Exchange Server 2007 Service Pack 1 (SP1) user clicks the Reply to All button to reply to a message that has more than 300 recipients in Outlook Web Access (OWA), the following HTTP 500 error is returned about two minutes later.
Microsoft Exchange issued an unexpected response (500).

If you click the
Show details button, the following information appears:
Request Url:  <OWA link> 
User host address: <Client IP>
User: <user name>
EX Address: <EX address>
SMTP Address: <SMTP address>
OWA version: 8.1.xxx.x Mailbox server: <Server name>

Exception Exception type: System.Web.HttpException Exception message: Request timed out. Call stack No callstack available

Cause

Exchange Server 2007 SP1 performs redundant Active Directory queries for recipients in order to prevent the duplication of messages. However, the check takes a long time when there are many recipients.

Resolution

To resolve this problem, install Update Rollup 9 for Exchange 2007 Service Pack 1. For more information about Update Rollup 9 for Exchange Server 2007 Service Pack 1, see the following Exchange Help topic: For more information about how to obtain the latest Exchange service pack or update rollup, see the following Exchange Help topic:

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Properties

Article ID: 969054 - Last Review: Aug 25, 2009 - Revision: 1

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