Unable To Download The Required Packages Because The Feed Is Disabled By Proxy With Status Code 407

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How to resolve the issue where feeds such as 'https://api.nuget.org/v3/index.json' are disabled by proxy and return status code 407?

Issue Description

While attempting to download packages from Manage Packages in UiPath Studio, the following error is displayed:

“Unable to load the service index for source {package source}”

The package feed URL remains accessible through a web browser, but Studio fails to retrieve packages.

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Studio logs may contain the following warning:

[WARN] Feed https://pkgs.dev.azure.com/uipath/Public.Feeds/_packaging/UiPath-Official/nuget/v3/index.json has been disabled. Reason: System.Net.Http.HttpRequestException: The proxy tunnel request to proxy 'http://proxy.address.com:8080/' failed with status code '407'. 



Symptoms


  • Packages cannot be downloaded from Official or custom feeds.
  • Error message: 'Unable to load the service index for source…'
  • Feed is automatically disabled in Studio.
  • Feed URL opens successfully in a web browser.
  • Studio logs display HTTP 407 – Proxy Authentication Required.


Root Cause


HTTP status code 407 indicates that the request is routed through a proxy server requiring authentication.


In this scenario:


  • Studio/Robot traffic is sent through a corporate proxy.
  • The proxy requires authentication.
  • Credentials are not supplied by the client application.
  • The proxy blocks the request, preventing retrieval of the NuGet service index.


This behavior indicates a network-level proxy authentication issue rather than a feed availability problem.


Resolution


Configure Studio/Robot to use Windows default credentials when communicating through the proxy.


Step 1 – Create System Environment Variable


Create the following system environment variable(Refer):


  • Name: UIPATH_PROXY_USE_DEFAULT_CREDENTIALS
  • Value: true


Method – Using PowerShell (Recommended)


  1. Open PowerShell as Administrator.
  2. Execute the following command:[Environment]::SetEnvironmentVariable("UIPATH_PROXY_USE_DEFAULT_CREDENTIALS", "true", "Machine") 


Step 2 – Restart Services


Restart one of the following to apply the configuration:


  • UiPath Robot Service
  • Reboot the machine


A restart is required because environment variables are loaded at process startup.




Step 3 – Verify Configuration


To confirm successful configuration, run: $Env:UIPATH_PROXY_USE_DEFAULT_CREDENTIALS


Expected output: true 


Validation


After restart:


  1. Open UiPath Studio.
  2. Navigate to Manage Packages.
  3. Confirm:

    • The Official feed is enabled.
    • Packages load successfully.
    • No HTTP 407 errors appear in Studio logs.
    







Applicability


This solution is applicable when:


  • The proxy uses Windows Integrated Authentication (NTLM/Kerberos).
  • The machine is domain-joined.
  • The user or service account has proxy access permissions.


Limitations


This resolution may not resolve the issue if:


  • The proxy requires explicit username/password authentication (Basic authentication).
  • The Robot service runs under an account without proxy permissions.
  • SSL inspection or certificate trust issues are present.
  • Firewall rules block outbound traffic to Azure DevOps package feeds.


In such cases, coordination with the network team is required to verify proxy authentication methods, account permissions, and required URL whitelisting.