Are you following the steps properly? You have to do this, exactly:
- Select the shape in LightBurn that represents the first target on your design
- Jog the laser to the location of that target on the laser
- Click the ‘Set First Target Position’ button
- Select the shape in LightBurn that represents the second target
- Jog the laser to the position of that target on the laser
- Click the ‘Set Second Target Position’ button
If you don’t change the selected object after step 3 OR you don’t jog the laser to a new location, you’ll get the “not enough separation” error.