[visual-studio] Getting "project" nuget configuration is invalid error

I'm getting "[project] nuget configuration is invalid" error. I received an error like this before and used the 'Update Nuget package manager' solution mentioned here:

Unable to Install Any Package in Visual Studio 2015

I've also tried the other solutions mentioned in that link to no avail.

• Restarting Visual Studio
• Deleting nuget.config
• Deleting packages.config
• Updating nuGet Package Manager.

Also, I'm able to see the nuGet Packages at the solution level and other projects within this solution.

And, if I go to Package Manager Console (Tools -> NuGet Package Manager -> Package Manager Console), I can't see the projects having this issue in the project drop down, but I see the other projects in the solution.

Simply restarting Visual Studio worked for me.