Windows Server 2012 R2 DataCenter The request to list features available on the specified server failed

Solution 1:

I'm pretty sure it's a stuck pending reboot request.

Go to "C:\Windows\WinSxS" and check if there's a pending.xml file. Delete that file and try rebooting again. If you're unable to delete that file, try deleting it offline. If it's a virtual server, simply map its virtual disk somewhere and delete the file that way.