Don't worry, the device is usually showing this error just because the synchronization is not set-up correctly. 

If the IMU receives the signal through the synchronization port it can show the errors (usually the error is system failure).

We would advise that you use Master clock or PPS sync options to achieve accurate synchronization.

In Master clock sync mode DS-IMU provides the absolute GNSS time and synchronizes the devices with it's PPS signal.

To set the master clock option in DS-IMU go to Extensions -> DS-IMU  and select sync mode as Masterclock

The synchronization setting of the whole system should be set to:

Time source: External

Clock provider: GPS PPS

In this case, I have DEWE-43 connected to the computer.

The sync cable from the IMU has to be connected into the device.

To use the PPS sync option just select the PPS sync inside the DS-IMU settings. System synchronization settings should stay the same. In the PPS sync mode, IMU still provides a PPS signal to the device and DEWESoft but the absolute clock of DEWESoft measurement will be equal to the current computer clock.