Error in Alarm Monitoring: ''Unable to send acknowledgment request to remote server...''


While attempting to acknowledge alarms in Alarm Monitoring, the following error may appear:

Unable to send acknowledgment request to remote server .

Clicking [OK] may not clear the error, or the error may continue to appear, which may cause Alarm Monitoring to hang or crash.

The following events may appear in Alarm Monitoring when an attempt is made to download the database to an access panel:

  • Database Error in Panel Download
  • Driver Error in Panel Download

The following error may also appear:

This alarm has already been acknowledged by another station.


If there is a single Communication Server in the OnGuard installation, restart the LS Communication Server service on the computer running the Communication Server.

If there are multiple Communication Servers in the OnGuard installation, perform the following steps:

  1. Determine which access panel is related to the alarm being acknowledged.
  2. Determine which computer is running the Communication Server that is being used by the access panel. This can be checked in System Administration, under Access Control > Access Panels, on the Location tab, in the Workstation field.
  3. Restart the LS Communication Server service on this computer.

If these steps do not resolve the issue, check the version of the Communication Server. Make sure that the build versions are the same on the Communication Server and the client machine that is acknowledging the alarms.

For example, if the Communication Server is at version 2.0.18 and the client machine is on version 2.4, you will see the errors listed above.

Verify the version of the Communication Server by cross-referencing the file dates in the OnGuard directories to those in the release archives:

Applies To

OnGuard 2008 (6.0.148) or later

Additional Information

his procedure may not resolve the issue for high-availability systems (Microsoft Cluster, NEC ExpressCluster). Contact LenelS2 Technical Support for assistance with this issue for high-availability systems.