I am getting teh following error "Failed to fetch data: In handler 'win-wmi-find-collection': Unable to get wmi classes from host . This host may not be reachable or WMI may be misconfigured." while getting data from remote performance monitoring.
There are many reasons why you might experience this error.
Have you installed your Splunk instance as a user with appropriate access to the performance monitoring objects you are trying to monitor (not "Local System")?
Have you granted the user that you installed Splunk as appropriate permissions to the performance objects you want to monitor?