No g code preview

Using snapmaker luban 3.4.2 and i am not able to get the preview after generating the g code for printing to show the layers.

Just shows the grey image of the file but no layers, works sometimes and i have no idea why it is doing it.

I even downgraded to 3.1.1 and still does the same thing.

Hey what OS do you use?
WIN, MAC, Linux?