You may notice that Agent scans are not working over the VPN, while scans on other machines are working properly.
Failing scans may be showing the error "The RPC server is unavailable".
1. Check that the ports are opened
Use the article What Ports and Protocols are Used by GFI LanGuard? for reference, and make sure the required ports are open.
2. Getting the error message "The RPC server is unavailable"?
If you are getting the error message "The RPC server is unavailable", consult the article Resolving the Error connecting to WMI server: 'The RPC server is unavailable' for a possible resolution.
3. Manually uninstall and re-install the Agent.
Use the article Uninstalling GFI LanGuard Agents as a reference.
If there are files missing from the installation, copy them from another healthy agent (Example: C:\ProgramData\GFI\LanGuard 12\Update\operationsprofile.7z).
4. Remove the machine completely from the console and re-add it.
Right-click on the machine in the Computer Tree and press "Remove".
Then, add the machine to the Computer Tree again.
5. Perform a scan and check whether results are reported in the activity monitor.
Refer to the Agent Scanning Overview.
6. Perform an interactive scan.
If the scan works properly, it will ensure that this is an Agent issue. See Performing a Manual Scan in GFI LanGuard, Interactive and Scheduled Scanning in LanGuard (Console).
7. Check connectivity.
Check connectivity by pinging the IP, and using NSlookup on the hostname and the IP.
Note: Confirm that you are using static IPs, or otherwise that the network configuration is compatible with LanGuard requirements.
Consult the article Can Agents Scan and Send Results over VPN to LanGuard Server Only by IP?
8. Try another Agent.
Attempt to perform the same steps on another Agent to observe any differences in behavior.
If the above steps do not produce a solution, please create a support ticket, including Server and Agent logs, according to these articles:
The scan result of the interactive scan may also prove helpful: Saving and Loading Scan Results in XML
Finally, please include Windows logs: How to Export Event Viewer Application and System Logs.
All the above should be provided for both the initial machine, and the alternative one involved in the final step - the comparison could help in case there were differences observed between the two.