Opera could not connect to proxy server. access denied

Guidelines to Troubleshoot Connectivity Issues - Tally.ERP

Fix: Unable to connect to Proxy Server in Windows 10 Jan 21, 2020 Direct Access Troubleshooting: Failed to connect to domain Dec 09, 2014

Opera 19 only error "Unable to connect to the proxy server

How to fix "Unable to connect to the proxy server" error

In these situations, the server (or a proxy server, in some cases) is still the network object that is producing the 407 Proxy Authentication Required and returning it as the HTTP response code to the client, but it could be that the client is causing the issue in some way.

Sep 05, 2009 FWPTT web load testing framework