title: Visual Studio 2013 - Error occurred while trying to restore packages. The underlying connection was closed.
body: <p>In <strong>Visual Studio 2013</strong>, NuGet package manager fails to restore packages. When clicking <strong>Manage NuGet Packages</strong> on the project, NuGet states &quot;<em>Some NuGet packages are missing from this solution. Click to restore from your online package sources.</em>&quot;. After clicking &quot;Restore&quot;, the following error appears...</p>
  <h3>Manage NuGet Packages Window</h3>
  <pre><code>Error occurred while trying to restore packages. The underlying connection was closed.
  </code></pre>
  <p>If you build the project, the output window shows the following errors...</p>
  <h3>Build Output Window</h3>
  <pre><code>Restoring NuGet packages...
  To prevent NuGet from restoring packages during build, open the Visual Studio Options dialog, click on the Package Manager node and uncheck 'Allow NuGet to download missing packages during build.'
  NuGet Package restore failed for project MyProject: The underlying connection was closed: An unexpected error occurred on a send..
  NuGet package restore failed.
  </code></pre>
  <p>Any ideas?</p>