Fix Windows Security Authentication Error 0x80070035 - PowerShell 407 Proxy Authentication Fix-Troubleshooting Pip and Python PATH Issues

Updated 2026-06-13 19:06:48macos-help
Fix Windows Security Authentication Error 0x80070035 - PowerShell 407 Proxy Authentication Fix-Troubleshooting Pip and Python PATH Issues
Before changing system settings, save your work and note the exact error text so you can compare results after each step.

Extra verification checklist

  • Restart the affected app after changing permissions or configuration files.
  • Test the same workflow in a clean browser profile or a temporary user account.
  • Compare the result on another network if the error may be connection related.