A few things to check.
Did your machine come with GRBL 0.9?
Did you update to 1.1f and leave the settings at default or change some?
Do your controller board have a switch to select laser or spindle?
If you place the laser in the middle of the work area and use the arrows in Lightburn Move window, do the right arrow jog to the right and the left arrow to the left and up to up and down to down?