After a few months after a PRTG update, I frequently receive false ping errors on PRTG, although I can ping the hosts directly from the PRTG server without issues. The errors usually resolve after 10-15 minutes.

You can usually resolve this issue if you ask the following questions:

  1. Is there an Antivirus System installed on the same system?

    If so, please disable it temporarily and observe if the behavior continues. Some antivirus systems block automated ping requests. This could also be caused by a firewall.

  2. Are only certain devices or sensors affected?

    If so, then please open a command line on the PRTG core server and issue ping for two or three of the affected hosts with the following command:

    ping -t HOST