What the 407 error means

How to fix HTTP 407 Proxy Authentication Required error: quick wins

• Check if you are on a network that uses a proxy. Try a different network (mobile hotspot) to see if the problem goes away.
• Enter your proxy username and password when prompted. Use the right format: DOMAINusername or username@domain if your company uses a domain.
• If you do not need a proxy, turn it off in system or app settings.
• Clear saved proxy settings and re-add them. Typos in host, port, or credentials cause 407.
• Restart your browser or app. Some apps cache proxy auth and need a restart to retry.
• If you use a VPN, disconnect and test. Some VPNs add a proxy or block proxy auth.

Why you see 407

Common causes

• Wrong or expired proxy credentials
• Mismatched username format (needs DOMAINuser or user@domain)
• Proxy is set but not reachable (bad host or port)
• Browser or app uses different proxy than your system
• Proxy requires a method your app does not support (for example, NTLM)
• PAC/WPAD file points to a non-working proxy
• Corporate TLS inspection needs a root certificate you have not installed

Fix it in your browser

Change system proxy settings (Windows)

• Open Settings > Network & Internet > Proxy.
• Turn off “Use a proxy server” if you do not need one. Or enter the correct Address and Port.
• If you use a setup script (PAC), make sure the URL is right and reachable.
• Click Save, then restart the browser.

Change system proxy settings (macOS)

• Open System Settings > Network > select your active network > Details > Proxies.
• Uncheck proxies you do not use, or enter the right host and port for HTTP and HTTPS.
• If you use a Proxy auto-configuration (PAC) file, verify the URL.
• Click OK and Apply, then restart the browser.

Firefox specific

• Open Settings > General > Network Settings > Settings.
• Choose “Use system proxy settings,” or set “Manual proxy configuration” with the correct host, port, and credentials.
• Add exceptions for local addresses in “No proxy for” (for example, localhost, 127.0.0.1, and internal hosts).

Fix it on Windows, macOS, and Linux

Windows (WinHTTP and credentials)

• Sync system proxy to WinHTTP: open an elevated Command Prompt and run: netsh winhttp import proxy source=ie
• To clear WinHTTP proxy: netsh winhttp reset proxy
• Update saved Windows Credentials for the proxy in Control Panel > Credential Manager if your company uses them.

macOS and Linux environment variables

• Check variables: echo $HTTP_PROXY $HTTPS_PROXY $NO_PROXY
• Set them (example): export HTTP_PROXY=http://user:pass@proxy.example.com:8080 export HTTPS_PROXY=http://user:pass@proxy.example.com:8080 export NO_PROXY=localhost,127.0.0.1,.yourcompany.com
• Unset if you do not need a proxy: unset HTTP_PROXY HTTPS_PROXY http_proxy https_proxy

Fix it in common tools

curl

• Test through proxy: curl -v -x http://proxy.example.com:8080 https://example.com
• Add credentials: curl -v -x http://user:pass@proxy.example.com:8080 https://example.com
• For NTLM or Negotiate: curl –proxy-ntlm … or curl –proxy-negotiate …

Git

• Set proxy: git config –global http.proxy http://user:pass@proxy.example.com:8080
• Clear proxy: git config –global –unset http.proxy
• For HTTPS: git config –global https.proxy http://user:pass@proxy.example.com:8080

npm and Yarn

• Set: npm config set proxy http://user:pass@proxy.example.com:8080 npm config set https-proxy http://user:pass@proxy.example.com:8080
• Clear: npm config delete proxy npm config delete https-proxy
• Yarn uses the same environment variables or .yarnrc settings.

pip (Python)

• Use: pip install –proxy http://user:pass@proxy.example.com:8080
• Or set HTTP(S)_PROXY environment variables as shown above.

Docker

• Set /etc/systemd/system/docker.service.d/http-proxy.conf with: [Service] Environment=”HTTP_PROXY=http://user:pass@proxy.example.com:8080″ Environment=”HTTPS_PROXY=http://user:pass@proxy.example.com:8080″ Environment=”NO_PROXY=localhost,127.0.0.1,registry.local”
• Then: systemctl daemon-reload && systemctl restart docker

Authentication and certificate tips

Get the username format right

• If your company uses Active Directory, try DOMAINusername in Windows apps.
• On macOS or Linux, try username@domain.
• Watch for special characters in passwords. If they break URLs, URL-encode them or use prompts instead of embedding in the URL.

Match the proxy auth method

• Basic: most clients support it.
• NTLM/Kerberos: some tools need extra flags or do not support them well. If needed, ask IT about a helper like CNTLM or a token-based method.

Trust the proxy’s TLS certificate

• Some companies inspect HTTPS traffic. You must install their root certificate in your system trust store.
• If your tool fails on SSL but you see 407 before that, fix certificate trust first, not by turning off SSL checks.

Advanced troubleshooting

Test with verbose output

• Run: curl -v https://example.com If you see “407 Proxy Authentication Required,” the proxy path is active.
• If you do not see any proxy in the logs, your app may not be using system proxy settings.

Check PAC/WPAD logic

• Open the PAC file URL in a browser to confirm it loads.
• Look for the proxy it returns for your target site. If it is wrong, ask IT to update the PAC.

Review bypasses

• Use NO_PROXY to skip the proxy for local or trusted domains: NO_PROXY=localhost,127.0.0.1,.intranet.local
• Wrong bypass lists can force traffic through a proxy that blocks it.

When to call IT

• You entered the right credentials but still get 407.
• Your app does not support the auth method the proxy requires.
• The PAC file or corporate root certificate needs an update.
• Others on your network have the same issue.

(Source: https://www.forbes.com/sites/digital-assets/2026/04/09/let-the-games-begin-a-massive-62-trillion-price-earthquake-is-suddenly-hurtling-toward-bitcoin/)

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