There is a problem with my machine

Hello there, Lately i’m having a problem with the x axis of the laser. When resetting, it won’t turn back to the same original location. It shift to the left instead. And when i cut a circle, it will be like an oval shape. I cleaned everything, thightened the belt but still the same. Can anyone help me diagnosing what the problem of the machine is?

Hello,Goodman.According to your problem description, I also need to know what board you are using. In addition, I will also attach a picture of the motor and a round setting picture. Please contact me in time if you have any questions.