You have an application that is built on the Microsoft .NET Framework 2.0 and that is hosted on Internet Information Services (IIS) 7.0. The first time that you access a Microsoft ASP.NET page in the application, you receive an HTTP 400 error message. However, later requests succeed.

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An application attempts to listen for local loopback requests by calling HttpAddUrl for http://localhost[:port]. If the application does not have administrator privileges the call will fail with the following:

Access Denied

This problem occurs on Windows Vista if User Account Control (UAC) is enabled and the application is running under the Limited User Account.

This problem occurs when the local computer is running one of the following Microsoft Windows operating system:

• Windows Vista
• Windows Server 2003
• Windows XP

When you try to send messages to the HTTP address or to the multicast address of a Microsoft Message Queuing queue on a computer that is running a 64-bit version of Windows Vista, the attempt is unsuccessful. Additionally, you receive the following error message:

404 not found

When you try to configure Windows Mail to use an Web-based e-mail account on a computer that is running Windows Vista, you experience one of the following symptoms:

• When you try to add a Hotmail account or an MSN account to Windows Mail, you receive the following message:
  

  Information About HTTP E-mail

  Windows Mail no longer supports the HTTP servers used by Hotmail and other web-based e-mail providers. Click the Back button to set up a different e-mail account, or see other options for accessing your web-based e-mail.

• When you try to use a Windows Live e-mail account or a different Web-based e-mail account in Windows Mail, you cannot send or receive e-mail messages.