Verify that you are trying to add the Windows device from a Cloudmon Windows probe. Confirm that the WMI credentials you provided are correct and that you can successfully connect to the device using the same credentials from any other Windows ...
There are different types of monitoring. If you want to monitor the latency, jitter and link connectivity, you do not require agents on the servers. But if you want to monitor, CPU, memory, network, system resources like disk, file system ...