When a client computer uses a SOAP Web Services Description Language (WSDL) moniker to activate a COM+ SOAP-enabled server on a computer that is running Windows Vista, server activation fails. Additionally, you receive an error page that resembles the following:

HTTP Error 404.11 – Not Found

Description: The request filtering module is configured to deny a request that contains a double escape sequence.

Error Code: 0×00000000

Notification: BeginRequest

Module: RequestFilteringModule

Requested URL:

Physical Path:

Logon User: Not yet determined

Logon Method: Not yet determined

Handler: HttpRemotingHandlerFactory-rem-Integrated

Most likely causes:

The request contained a double escape sequence and request filtering is configured on the Web server to deny double escape sequences.
What you can try:

Verify the configuration/system.webServer/security/requestFiltering@allowDoubleEscaping setting in the applicationhost.config or web.confg file.

More Information… This is a security feature. Do not change this feature unless the scope of the change is fully understood. You should take a network trace before changing this value to confirm that the request is not malicious. If double escape sequences are allowed by the server, modify the configuration/system.webServer/security/requestFiltering@allowDoubleEscaping setting. This could be caused by a malformed URL sent to the server by a malicious user.

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Server Version Information: Internet Information Services 7.0.