I was getting below error.
"advance group policy management" "could not enable.net for windows activation service". "enable manually"
If you get this error message just install the .net 3.5 from server manager and it will work.
sometime it will just not install it by checking on server manager.
So provide alternate path for Windows OS disk. eg: d:/source/sxs
OS: windows server 2012 R2
AGPM 4.0 SP3 Server and client component.
On installation you will not see the change control.
Now you will see the change control after installing the client.
Hope this helps you.