Based on everything I have seen here it looks like Lightburn is working properly. I am thinking it’s either not speaking the same G-code commands your laser wants to see (setup issue) or there is some other communication issue between Lightburn and the Laser. I would go over the setup again (also ask Lightburn support if it’s compatible with that particular laser or if there is something in setup that needs to be changed). I use CO2 lasers with a Ruida controller so this issue is not really my area of expertise.