NuGet packages Xamarin.Android.Support.xxx updates from 26.1.0.1 to 27.0.2 fail

Hello,

I cannot update Xamarin.Android.Support.xxx packages from 26.1.0.1 to 27.0.2:

Install failed. Rolling back...
Package 'Xamarin.Android.Support.Fragment.27.0.2 :
Xamarin.Android.Support.Compat [27.0.2, 27.0.2],
Xamarin.Android.Support.Core.UI [27.0.2, 27.0.2],
Xamarin.Android.Support.Core.Utils [27.0.2, 27.0.2]' does not exist in project 'my.project'

The "Build" android package fails as follows:

This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them. For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is ..\packages\Xamarin.Android.Support.Media.Compat.27.0.2\build\MonoAndroid81\Xamarin.Android.Support.Media.Compat.targets.
my.project
C:\mypath\mysolution\Droid\my.project.csproj
246

I'm running Visual Studio 2017 Version 15.6.2.

Thank you!