running on remote machines

I am trying to run Invoke-Command on a few remote machines and I keep getting this error.

The WS-Management service cannot process the request. Cannot find the Microsoft.PowerShell session configuration in the WSMan:

I have logged onto one of the remote machines and I've run the following. winrm quickconfig.

C:\WINDOWS\system32>winrm quickconfig
WinRM service is already running on this machine.
WinRM is already set up for remote management on this computer.

I have started PowerShell and run Set-ExecutionPolicy Unrestricted

I have confirmed that the Windows RM Services is up and running.

Yet I still get the error above.