• Access "Vendor param" (password: rd88888) and click "Motor".
• Sequentially click "X", "Y", "Z" (if applicable), and "U"(if applicable).
• In the window that opens, tick the box before PWM rising edge valid" if it is not ticked. Untick it if it is ticked (as shown).

• If the problem persists, test with RDworks. If RDworks works, the problem was with LightBurn.
• Load LightBurn.
• Access "Optimization settings" and enable hide backlash (as shown).

If RDWorks does not work either, cut a 100×100mm square and measure if the lengths of the two diagonals are consistent.

If not.

1. Loosen the Y-axis connector
2. Holing one end of the X-axis still, move the other end to make the X-axis perpendicular to the Y-axis.

If the lengths are consistent, adjust the belt tension. If this fails, replace the belt with a new, identical one.