The samples and the SilverlightWebService URLs use default HTTP port 80 to communicate. If you use a different port for the web site from which the samples and the service are running, please make sure to change the samples URL files and webServiceUrl string used by ImGearLicense.SetService() call in the sample code (Page.xaml.cs) to explicitly specify the port number (by adding ':<port number>' after the hostname), and rebuild the samples. You may also need to clear the browser's cache.