Foreign objects such as dirt and hair can easily become tangled or stuck in the side brushes. Clean the side brushes regularly.
Unscrew the screws with a Phillips screwdriver.

Carefully rotate and pull out the hair or thread tangled between the robot cleaner and the side brushes.

Use a cloth dampened with warm water to remove dust on the brushes or straighten them gently.

Make sure the side brush is completely dry before use.