This error may occur on machines that have a firewall enabled.

Problem: Invalid connection settings in WebConfig.xml.

Fix: Open WebRemoting.config and ensure the connection settings are correct.

Problem: IIS wasn’t reset after configuration.

Fix: Each time WebRemoting.config is modified, IIS must be reset.

Problem: The Windows Firewall has not been configured to allow web clients to access the web server.

Fix: In the Control Panel, configure Windows Firewall to allow web clients access to the web server. Procedures are available in the Configuring Responder online documentation (Web Server section).