Error -1967353911 When Using Modbus I/O Servers in LabVIEW

Issue Details

I have a code in LabVIEW that utilizes a Modbus I/O Server to establish communication with an external device. The project has worked fine for several months, but suddenly, it stopped to function properly, and I started to receive error -1967353911. If I use a third-party software to test the communication with my device everything works, so I know that the configuration I set for my I/O Server in LabVIEW is correct since it is the same I have selected for the third-party software.  I am not sure why LabVIEW is failing to communicate. The error message is presented below:

Error -1967353911 occurred at an unverified location

Possible reason(s):

LabVIEW DSC: The Modbus I/O server failed to send a frame. Ensure that the configuration of the specified serial port for modbus master is correct.

Solution

The issue may be related to the NI Variable Engine not running or being in an unknown state. To solve the issue, you can try the steps below:

1. Launch the Windows Services. You can type Services in the Windows search bar to open the right app. 
2. Look for the NI Variable Engine service and verify that it is running. 

• • If the service is not running, right-click on it and select Start to initialize it. 

• • If the service is running, select Restart to automatically stop and start the service.