Movment issues with GRBL

I have a WorkBee that has an x of 546mm and a y of 749mm.I’m having trouble setting uup the machine for Lightburn. It seems that no matter what I do it wants to drive off the work surface. It will overide the the limit switches and keep grinding into sides or ends. . I’ve read the specific docs for GRBL at Lightburn, but everything I try isn’t working. Itt’s so fustrating because it works perfectly in the Open builds control software and Easel and UGS. I am using an Open builds black box. Here’s a few starter pics.

Thanks so much!