Microsoft Exchange ActiveSync crashes on a Microsoft Exchange Server 2007 server. Therefore, the client synchronization is unavailable. Additionally, you find the following event in the Application log:When this problem occurs, if you try to run the Test-ActivesyncConnectivity Cmdlet in Exchange Management Shell, you may receive the following error message:
[System.Net.WebException]: The remote server returned an error: (503) Server Unavailable.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.