Getting a 407 Error - Proxy Authentication Required. How Do I Fix This? or Why Am I Seeing a 407 Erro

If you’re seeing the 407 error on certain sites only, it’s likely a proxy whitelist issue. Some work networks block random stuff.

Try accessing the site on your phone using mobile data. If it works, then yeah, it’s your network’s proxy.

Otherwise, this tool helped me debug: https://www.proxysite.com/ (just to test if it’s proxy-related).