Namespace Newtonsoft is Missing

[zoid66]

I am getting this error when I enter play in any one of two example scene "Assets\Spotify4Unity\Core\Managed Authentification\PKCE\PKCE_Authentification.cs(1,7): error CS0246: The type or namespace name 'Newtonsoft' could not be found (are you missing a using directive or an assembly reference?)"

[Makarova13]

Just find the Newtonsoft.dll and add it to the Packages folder

[GenebrisGit]

Above comment doesn't make sense and documentation fails to list this requirement, but you just need to install this Unity package:
https://docs.unity3d.com/Packages/com.unity.nuget.newtonsoft-json@3.2/manual/index.html

Go to "Add package by name" in package manager and use this name
com.unity.nuget.newtonsoft-json