I've had PRTG running for a while and suddenly I'm getting a few servers that report the error below. On the servers that fail, all WMI probes fail. It's not all servers that fail though, most are ok.
A reboot of the server doesn't help.
Connection could not be established (800706BA: The RPC server is unavailable) (code: PE015). It appears that you are experiencing some difficulties with WMI or related areas. For more information, see https://kb.paessler.com/en/topic/60153