Error message when you try to visit a Web page that is hosted on IIS 7.0: "HTTP Error 404.8 – HIDDEN_NAMESPACE"


Symptoms


When you try to visit a Web page that is hosted on Internet Information Services (IIS) 7.0, you may receive the following error message:
Server Error in Application "<application name>"
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HTTP Error 404.8 – HIDDEN_NAMESPACE

HRESULT: 0

Description of HRESULT

# The operation completed successfully.

Cause


This problem occurs because the Request Filtering feature is configured for the Web server. Additionally, the Request Filtering feature contains a <hiddenSegments> element. The <hiddenSegments> element lets the administrator of the Web server deny access to a directory that is specified in the requested URL.

Resolution


To resolve this problem, follow these steps:
  1. Click Start, type Notepad in the Start Search box, right-click Notepad, and then click Run as administrator.


    Note If you are prompted for an administrator password or for a confirmation, type the password, or click Continue.
  2. On the File menu, click Open, type %windir%\System32\inetsrv\config\applicationHost.config in the File name box, and then click Open.
  3. In the ApplicationHost.config file, locate the <requestFiltering> element, and then locate the <hiddenSegments> element.
  4. In the <hiddenSegments> element, delete the entry that matches the directory that is specified in the requested URL.
  5. On the File menu, click Save.
  6. Exit Notepad.