Q: What does a “Could not download page (407)” error mean? A: A 407 message means Proxy Authentication Required and that the proxy needs you to sign in. This guide explains how to fix “Could not download page (407)” proxy error by checking the proxy address, refreshing credentials, testing without the proxy, and updating app settings. Q: Which apps or tools commonly show a 407 proxy error? A: A 407 can appear in browsers, command-line tools (curl, wget, Git, npm, pip), app stores, or package managers because network traffic is routed through a proxy. The proxy blocks the request until you authenticate, so the error can show across different tools when proxy settings or credentials are wrong. Q: How can I confirm whether the proxy is causing the 407 error? A: Try another site to see if all pages fail or just one, and check whether the error appears in a browser, a CLI tool, or a single app. Test with your VPN on and off and try a different network to isolate whether the proxy is at fault. Q: How do I verify the proxy address, port, and PAC settings? A: Find the proxy settings in your system or app and confirm the host and port are correct and that you’re using the right scheme (many proxies are http://host:port even for HTTPS). If you use a PAC file, open it to ensure your target site matches a DIRECT rule or the intended proxy, since incorrect details commonly cause 407 responses. Q: What should I do about credentials when I get repeated 407 prompts? A: Sign in with the correct username and password and include the domain if needed (DOMAINuser or user@domain), then update saved credentials in your browser or credential manager. For company SSO, open a browser and sign in to the portal before retrying the download, and clear saved proxy credentials if prompts repeat. Q: How can I temporarily bypass the proxy to test connectivity? A: Turn off “Use a proxy” in your system or app settings or add the target host to the NO_PROXY bypass list, then retry the site to see if it works directly. You can also try a different network, such as a mobile hotspot, to confirm whether the problem is the proxy or the remote server. Q: Which environment variables affect proxy behavior and how should I check them? A: Check HTTP_PROXY, HTTPS_PROXY, and NO_PROXY environment variables (both upper and lower case) because they can override app settings, and make sure values include a scheme like http://proxy.company.com:8080. If they are wrong, fix or unset them and use NO_PROXY to skip the proxy for internal hosts. Q: When should I contact my network admin and what information should I provide? A: Contact your network admin if the site is blocked or needs allow-listing, if SSL inspection requires an approved root certificate, or if a PAC file needs an update. If the 407 appeared after a password change, wait for directory sync or log out/in and provide the exact 407 response and timestamps to help them troubleshoot.