What if my Chuango Robot Vacuum RV-500 beeps twice with a red flashing indicator? Modified on: Tue, 18 Jan, 2022 at 10:18 AM Bumper error. Please check if the bumper is blocked.1. Check if the bumper can be pressed down. If not, it might be blocked by some objects.2. Tap device’s bumper several times to dislodge any debris that may be trapped underneath.