Yeah, this one's common. That red sweeping light means the robot senses its bin is full and needs to be emptied, but something's blocking the process.
First, manually empty the bin. Press the bin release button, pull the bin out, and open the bin door to empty it. Tap the filter against your trash container to dislodge fine dust. Make sure the bin door closes completely.
If that didn't work, the full bin sensors are dirty. Every two weeks, you need to wipe the inner sensors with a clean, dry cloth. Remove the bin, open the bin door, and you'll see the sensors inside. Give them a good wipe.
Heads up: Never wash the filter. Remove it before washing the bin with warm water (the bin is not dishwasher safe). The robot will not run if the filter is not installed correctly with the ridged grips facing out.