- You have multiple Active Directory sites in a Microsoft Exchange Server 2010 environment that has Update Rollup 3 for Exchange Server 2010 Service Pack 2 or a later-version update rollup installed.
- The Outlook Anywhere feature is enabled on the Client Access servers in each site.
- You use Outlook Anywhere to connect to a mailbox through the Client Access server that is located in the same site as the mailbox.
- You try to open another mailbox that is located in a different site and that you have sufficient permissions to access. For example, you try to open a shared mailbox that is located in a different site.
Additionally, the following event is logged in the RPC Client Access log on the Client Access server:
- Click Start, click Run, type regedit in the Open box, and then click OK.
- Locate and then select the following registry subkey:HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeRPC\ParametersSystem
- On the Edit menu, point to New, and then click DWORD (32-bit) Value.
- Type EnablePreferredSiteEnforcement, and then press Enter.
- In the Details pane, right-click EnablePreferredSiteEnforcement, and then click Modify.
- In the Value data box, type 0, and then click OK.
- Exit Registry Editor.