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IIS Application Pool




we have one IIS Server with an application pool. This pool contains some websites, an application for warehouse management. Every site is the same application, the only difference is the screen size and layout for different devices, i.e. scanner, PC, Touch Panel. Every site has a own URL. These sites are monitored with the PRTG sensor "Leistungsindikator IIS-Anwendungspool".

Every day we got 1-2 times an alarm from PRTG, the sites are not available, one site after the other, with 1 minute between the alarm message for every site. The message for all sites is the same:

"Unable to connect to the specified computer, or the computer is offline. (Leistungsindikator-Fehler # 0x800007D0)"

The trigger is definied for E-Mail and push information if the sensor is 600 seconds in error state.

All sites are fully available during the error condition. I have checked this several times from different clients and also from PRTG server, only PRTG thinks they are not.

Is there a known problem with this sensor?


alerts error iis iis-app-pool

Created on Jan 19, 2021 9:02:02 AM

1 Reply



Hello, we don't have any known issues like this on these sensors. It seems like the PRTG is losing connectivity with these devices for that period of time. Or perhaps not the whole connectivity with the device, but mostly with the IIS protocol on that machine.

Check if the Ping sensor remains connected during that time, if it does, it means there are no issues with the network, and the problem might be with the IIS service not responding the requests on time, or that the PRTG is having a delay in the monitoring.

This delay may happen if the server is lacking resources or if there are too many requests per second and at a certain point the PRTG drops some requests. In order for us to know for sure, we'd need to check the configuration on the PRTG. It would be better to submit a support bundle on a ticket to [email protected] to analyze it.

Created on Jan 21, 2021 9:28:52 PM by  Jonathan Mena [Paessler Technical Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.