Most issues with the force probe are caused by not calibrating it or calibrating it incorrectly. To learn more about calibrating your force probe, see the help article Calibrating Your iOLab Remote.
The most common issue with the force probe is that data collected forms a large blue rectangle in the viewer. It may also appear that the graph is blank. This is caused by extremely large force measurements being collected in error. If your force probe is uncalibrated or not calibrated properly, you can end up collecting data that looks like this:
Zooming out on this data shows us the large values.
You can fix this by Calibrating Your iOLab Remote. Make sure to follow the instructions carefully. If you already calibrated recently, you may have clicked through too quickly and made a mistake.