Assume that you run Microsoft Office Outlook Web Access (OWA) in Exchange Server 2010 Service Pack 1 (SP1) by using Internet Explorer 9. When someone sends you an instant message, you do not receive a new incoming message pop up as expected. Instead, you receive the following error message:
HTTP Error 400 Bad Request
This issue occurs because Internet Explorer 9 changes the way that the caller path is prepended to the URL. However, OWA does not call the functions that respond to the message.
To resolve this issue, install the following update rollup:
2529939 Description of Update Rollup 3 for Exchange Server 2010 Service Pack 1
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.