"Could not connect to a directory server" error message when you click the “last page” button in the search results in Exchange Server 2007 OWA


Consider the following scenario:    
  • You have a domain controller that is running Windows Server 2008 R2 in a Microsoft Exchange Server 2007 environment.
  • You log on to a mailbox by using Microsoft Office Outlook Web Access (OWA), and then you open the global address list (GAL).
  • You type a search term, and more than one page of search results is returned.
  • You click the “last page” button.
In this scenario, you receive the following error message:

Could not connect to a directory server. If the problem continues, contact technical support for your organization.


This issue occurs because Exchange Server 2007 changes the query parameters between pages. Therefore, strict search hash checking fails on the Windows Server 2008 R2-based domain controller.


To resolve this issue, install the following update rollup:
2509911 Description of Update Rollup 4 for Exchange Server 2007 Service Pack 3


To work around the issue, disable strict search hash checking on all Windows Server 2008 R2-based domain controllers in the Exchange Server 2007 environment. To do this, add the following registry subkey on all the Windows Server 2008 R2-based domain controllers:

Subkey path:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\NTDS\ParametersType: REG_SZ
Name: DSA Heuristics
Value: 000000000001


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