What is the abnormal material that was found on the conveyor belt during the width adjustment machine code of KM-ASSYH2-07 error id of 21?

What is the function of the width adjustment machine code, and how does it affect the conveyor belt?
The solution for the M7020 error involving abnormal material on the conveyor belt during width adjustment is to remove the material, reset any manual settings, and perform an emergency stop to prevent further problems. Once the issue is resolved,