dotnet restore does not try all sources for restoring

Steps to reproduce

1-Create a project that references packages from public nuget, some myget feed and a private feed that requires authentication.

2-Add Nuget.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <packageSources>
    <add key="NuGet" value="https://api.nuget.org/v3/index.json" />
    <add key="myget" value="https://www.myget.org/F/***/api/v3/index.json" />
    <add key="auth" value="https://nuget.***.com/nuget" />
  </packageSources>
  <packageSourceCredentials>
    <auth>
      <add key="Username" value="****" />
      <add key="Password" value="****" />
    </auth>
  </packageSourceCredentials>
</configuration>

Note that the auth feed uses version 2.

3-Run the following dotnet restore --configfile NuGet.config

Expected behavior

Packages are restored.

Actual behavior

dotnet restore tries to use only the auth feed to restore packages that reside in public nuget/myget.

Retrying 'FindPackagesByIdAsyncCore' for source 'https://[auth-feed]/FindPackagesById()?id='Microsoft.EntityFrameworkCore.SqlServer''.
Key not valid for use in specified state
Retrying 'FindPackagesByIdAsyncCore' for source 'https://[auth-feed]/FindPackagesById()?id='Microsoft.EntityFrameworkCore.SqlServer''.
Key not valid for use in specified state
Retrying 'FindPackagesByIdAsyncCore' for source 'https://[auth-feed]/FindPackagesById()?id='[myget-package-1]''.
Key not valid for use in specified state
Retrying 'FindPackagesByIdAsyncCore' for source 'https://[auth-feed]/FindPackagesById()?id='[myget-package-1]''.
Key not valid for use in specified state
Retrying 'FindPackagesByIdAsyncCore' for source 'https://[auth-feed]/FindPackagesById()?id='[myget-package-2]''.
Key not valid for use in specified state
Retrying 'FindPackagesByIdAsyncCore' for source 'https://[auth-feed]/FindPackagesById()?id='[myget-package-2]''.
Key not valid for use in specified state
C:\dotnet-sdk\sdk\1.0.0\NuGet.targets(97,5): error : Failed to retrieve information about '[myget-package-1]' from remote source 'https://[auth-feed]/FindPackagesById()?id='[myget-package-1]''. [D:\a\1\s\***.sln]
C:\dotnet-sdk\sdk\1.0.0\NuGet.targets(97,5): error :   Key not valid for use in specified state [D:\a\1\s\***.sln]

Environment data

dotnet --info output: 1.0.0

I should add that this error does not happen on my local machine, in fact it runs just fine. It only happens on VSTS, I use the dotnet-install.ps1 script to install 1.0.0 as following:

dotnet-install.ps1 -version "$(SdkVersion)" -installDir $(SdkPath) -Architecture x64 where: SdkVersion=1.0.0 SdkPath=C:\dotnet-sdk

Am I doing something wrong here…?

[TheCriticalPath]

Has anyone seen a resolution or workaround when using a docker container for builds?

[ImAMightyPirate]

Just in case anyone else ever finds this error via Google. We encountered this error because someone had missed a trailing forward slash from one of our NuGet feed URLs (hosted on ProGet) making it an invalid URL.