title: The package source named 'NuGet' is either invalid or not available
body: <p>I have installed Nuget 1.2 yesterday, and today, while I was trying to install Entity Framework package, I have encountered the following problem in the Package Manager Console:  </p>
  
  <blockquote>
    <p>PM> install-package entityframework<br>
    Install-Package : The package source named 'NuGet official package source   [https://go.microsoft.com/fwlink/?LinkID=206669]' is either<br>
    invalid or not available and thus is currently unreachable.<br>
    At line:1 char:16<br>
    + install-package &lt;&lt;&lt;&lt;  entityframework<br>
        + CategoryInfo          : NotSpecified: (:) [Install-Package], InvalidOperationException<br>
        + FullyQualifiedErrorId :   NuGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand  </p>
  </blockquote>
  
  <p>I can surft the internet and I don't think anything is preventing Visual Studio to access the internet.</p>