Please watch the instruction video to do troubleshooting : 

1. Turn the robot on 
2. Check if the radar rotate normally If no, there maybe some foreign objects stuck. 
3. You would need to open the cover of the robot to verify.
4. Gently push the lid of the radar to see if it can pushUse a screwdriver to remove the screws and open the transparent cover.
5. Please check if there is dust or hair stuck in the 3 switches of the radar. 
6. If the error is that the radar is covered, please clean the radar lens with a clean cloth 

If it still not work, could you kindly take the video again when you do troubleshooting and send it to so can get a faster solution, please?