Posts By Vince Vriend

The Problem

While working on a project which is being developed at the location of the client i ran into an annoying issue. The mandatory corporate web proxy is probably to blame.

dotnet restore for .NET Core projects started producing 407 (Unauthorized) errors, which sucks a lot because restoring packages is an essential step of building the project.

[14:40:12][Step 1/1] Restoring packages
[14:40:15][Step 1/1] Restoring packages for C:\BuildAgent\work\638151be47d2c658\Project1.csproj...
[14:40:15][Step 1/1] Restoring packages for C:\BuildAgent\work\638151be47d2c658\Project2.csproj...
[14:40:15][Step 1/1] C:\Program Files\dotnet\sdk\2.1.300\NuGet.targets(114,5): error : Unable to load the service index for source https://api.nuget.org/v3/index.json. [C:\BuildAgent\work\638151be47d2c658\Solution1.sln]
[14:40:15][Step 1/1] C:\Program Files\dotnet\sdk\2.1.300\NuGet.targets(114,5): error : Response status code does not indicate success: 407 (Unauthorized). [C:\BuildAgent\work\638151be47d2c658\Solution1.sln]

I got the same error in a slightly different form as well.

[11:15:03][Step 1/1] Retrying 'FindPackagesByIdAsync' for source 'https://api.nuget.org/v3-flatcontainer/autofac.extensions.dependencyinjection/index.json'.
[11:15:03][Step 1/1] Response status code does not indicate success: 407 (Unauthorized).
[11:15:03][Step 1/1] Retrying 'FindPackagesByIdAsync' for source 'https://api.nuget.org/v3-flatcontainer/system.security.cryptography.cng/index.json'.
[11:15:03][Step 1/1] Response status code does not indicate success: 407 (Unauthorized).
[11:15:03][Step 1/1] C:\Program Files\dotnet\sdk\2.1.300\NuGet.targets(114,5): error : Failed to retrieve information about 'Autofac' from remote source 'https://api.nuget.org/v3-flatcontainer/autofac/index.json'. [C:\buildAgent\work\a2846c1c6e7d5294\Solution2.sln]
[11:15:03][Step 1/1] C:\Program Files\dotnet\sdk\2.1.300\NuGet.targets(114,5): error : Response status code does not indicate success: 407 (Unauthorized). [C:\buildAgent\work\a2846c1c6e7d5294\Solution2.sln]

The Solution

I found one machine that was still able to build the project. It had version 2.1.201 of the .NET Core SDK installed.
The broken machines had version 2.1.300.

I downgraded all machines to .NET Core SDK version 2.1.201 and the problem was gone.

Other Things I Tried

Configure proxy authentication for nuget

The HTTP error code 407 litterally means Proxy Authentication Required.

In my case the nuget proxy is configured in c:\users\{username}\AppData\Roaming\Nuget\NuGet.Config but there are more possible locations

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <packageSources>
	<add key="Internal Package source" value="http://nuget.internal.nl/nuget" />
	<add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
  </packageSources>
  <config>
	<add key="http_proxy" value="http://proxy:8080" />
	<add key="http_proxy.user" value="DOMAIN\USER" />
  </config>
</configuration>

Remove all cached packages

Running nuget locals all -clear and/or dotnet nuget locals all --clear
It did not help.