How to resolve; Functionality is not implemented in the portable version of this assembly

Question

I added the firebase pushnotifications plugin to my application. This works fine in Android, however when testing for UWP the application keeps crashing on this line in my App.Xaml.cs

CrossFirebasePushNotification.Current.OnTokenRefresh += Current_OnTokenRefresh;

This is the error message:

System.NotImplementedException: 'This functionality is not implemented in the portable version of this assembly. You should reference the NuGet package from your main application project in order to reference the platform-specific implementation.'

I have cleaned & rebuild the solution. Deleted my project entirely and recloned it from github. The Nuget package is installed on the mobile, android & UWP project, all 3 having the same version.

Thanks in advance