Ender 3 laser don’t start

Hi all!
I have just built a laser module on my Ender 3 printer by using the fan port.
Now everything seems to work, manual put on and off the laser by command M106 works perfect.
But when executing a generated G-code, the laser will not get switched on.
I think the problem is that the wrong command is given by the Lightburn software but I can not find the setting…
Also the homing button does not work, it will give a message Unknown command $H.
Setup is:
Laser : GRBL-M3 (1.1e or earlyer)
Hope you can help me out!