My Sculpfun S9 started locking up when I send a job to it. Both X and Y axis. I asked Sculpfun for help and they suggested reflashing it, which I have done. Still the same issue. The laser works ok with GRBL.I am using the latest version of Lightburn.
That sounds like a strange issue. Usually, this happens with a fried mainboard, but if it works with LaserGRBL, it seems to be a software issue. First, I suggest re-installing LightBurn. Next, check this guide if all settings are correct: Setting up the software - Diode Laser Wiki
Additionally, post some screenshots of the settings you used.