Every now and then my WMI sensors go into the Down status and report a "Connection could not be established" error. Why is that and what can I do about it?
"Connection could not be established" (code: PE015) means that somehow the RPC server on either the host machine or the domain controller could not be accessed.
If these errors seem to appear sporadically there's something gone awry in your network/DCOM for a couple of minutes which PRTG dutifully reports as "sensor down".
PRTG tries to rebuild a faulty connection immediately, then again after 10 minutes, then after 20 etc.
If these errors vanish after a "Check now" you might prolong the latency settings for those sensors, so you won't get notified too quickly.
Sometimes, this error also occurs when using an IP address to connect to a device. If this is the case, you can try using the hostname or FQDN instead. For further troubleshooting, please have a look here.
Note: WMI being dependent on DCOM communication and Microsoft's update patches means an awfully complex breeding ground for all sorts of errors. We here at Paessler's are constantly working on improving PRTG in order to discover, identify, avoid, circumnavigate, and be as tolerant as possible about these errors (without compromising the main mission of PRTG, of course).
