The Z-axis is 1 mm lower on one side.

Hi there. I hope you can help me. I have a new Stepcraft M1000 with the upgraded drive system. However, I’m having an issue with calibration. When I set the X and Z positions all the way to the left and set the Z height to the surface level, and then start moving the X axis to the right, the cutting tool starts to cut into the board in the second third of the board. So, it seems as if the board on the right side is 1 mm higher, but that’s not the case. It looks more like I need to slightly lower the X gantry by about 1 mm on the right side to achieve a level surface. Is there a way to calibrate this or adjust the gantry? What are my options? Thanks for the help.