title: Access to private feed from Azure Devops pipeline
body: <p>I want to create access to my private feed from pipeline (Project A), but everytime when i try run <code>dotnet restore</code> to restore .net project with nugets from private feed (project scoped feed in Project B) i got</p>
  <pre><code>error NU1301: Unable to load the service index for source &lt;&lt;url_to_my_feed&gt;&gt;
  </code></pre>
  <p>My pipeline.yml looks like:</p>
  <pre class="lang-yaml prettyprint-override"><code>[previous jobs]
  
  - task: NuGetAuthenticate@0
  
  - task: Docker@2
    displayName: Build image
    inputs:
      command: build
      containerRegistry: $(dockerRegistryServiceConnection)
      repository: $(contentHostRepositoryName)
      Dockerfile: &quot;$(Build.SourcesDirectory)/src/modules/content/src/Dockerfile&quot;
      arguments: '--build-arg PAT=$(VSS_NUGET_ACCESSTOKEN)'
      tags: |
         $(tag)
  
  [next jobs]
  </code></pre>
  <p>My dockerfile looks like:</p>
  <pre class="lang-yaml prettyprint-override"><code>...
  ARG PAT
  RUN dotnet nuget add source &lt;&lt;url_to_my_feed&gt;&gt; --name &lt;&lt;name&gt;&gt; --username &lt;&lt;username&gt;&gt; --password $PAT --store-password-in-clear-text
  ...
  
  </code></pre>
  <p>When i replace <code>'--build-arg PAT=$(VSS_NUGET_ACCESSTOKEN)'</code> to <code>'--build-arg PAT=&lt;&lt;pat_token&gt;&gt;'</code> where <code>&lt;&lt;pat_token&gt;&gt;</code> is token, who i generate manualty to my personal account in Azure Devops - everythink work fine.</p>
  <p>What i try:</p>
  <ul>
  <li>using $(System.AccessToken) instead $(VSS_NUGET_ACCESSTOKEN)</li>
  <li>in feed set contribution permission to Project A Build Service</li>
  <li>in project B disable <code>Limit job authorization scope to current project for non-release pipelines</code> and <code>Limit job authorization scope to current project for release pipelines</code></li>
  <li>use <code>NuGetAuthenticate@0</code> and <code>NuGetAuthenticate@1</code></li>
  <li>into Pipelines Security in Project A allow Project Build Service for everythink</li>
  <li>before using $(System.AccessToken) main into varaible</li>
  </ul>