Turn off the device to avoid short circuiting the leads of the hall sensor.

Use blunt tweezers to finely adjust the hall sensor position along the tangential (cyan) axis as shown in the image:

If J is too much to the right, push the hall sensor toward the centre of the device (yellow arrow).

If J is too much to the left, pull the hall sensor towards yourself (magenta arrow).

Make sure to keep the same distance on the transversal (red) axis.