NuGet add reference error while installing packages

Question

I am not able to install any package by Nuget. For example when I want install entity framework I receive following error:

install-package EntityFramework
Su         


        

Answer 1

I also ran into this case when installing the AttributeRouting package. After googling a while, i tried the following steps and it works for me:

1. Tools > Extensions and Updates: uninstall NuGet Package Manager and reinstall it. Restart the Visual Studio.

2. Tools > Options > Package Manager > Package Sources: make sure to check for the nuget.org source.

Hope this help.