When using QNetworkProxyFactory::systemProxyForQuery() method to determine the actual operating system proxy settings, the proxy settings are only detected once by the QWindowsSystemProxy class. However when changed the operating system proxy settings in the 'Control Panel -> Internet Options -> Connections -> LAN Settings -> Proxy server', the running application still uses the settings, which were valid, when the application was started. The user has to restart the application to get the new proxy settings loaded.