Proxy server denies the connection
If you receive the error message “Proxy server denies the connection,” something is incorrectly configured in your proxy settings. You can change this under Windows in Control Panel or, in some cases, as a Firefox user in your browser.
Causes and solutions for the proxy server denying the connection
If you have mistakenly set the proxy server to the wrong setting, even though you may not use any proxies at all, you may experience problems loading websites. Before doing so, make sure that you have installed an extension in your browser, such as free proxy site, which automatically makes changes to the settings. If errors occur, you should deactivate such extensions first.
Open the Control Panel. Press the Windows key, tap “Control Panel” and click on the appropriate entry. Go to the “Network and Internet” menu and then “Internet Options”. Firefox: Websites are not loading because the proxy server is denying the connection
For Firefox users, it can sometimes happen that the proxy settings change after an update. Follow the steps below to solve the problem. Start Firefox and open the settings in “Tools”.
Switch to “Advanced” and in the “Network” tab, in the “Connections” section, click on “Settings”. Then check the box next to “Use system proxy settings”.