This procedure verifies that the username/password combination are correct, and that there is no firewall blocking the connection. Since this is done from the Zenoss server, this test is a better approximation of how successful Zenoss will be in connecting to the Windows device.
As the zenoss user on the Zenoss server:
wmic -U 'user
' //device
'select * from Win32_computerSystem'
The wmic command will then prompt you for the password.
This procedure is only valid for Zenoss 2.3 or greater.