Adding on,
If everything checks out, make sure there is absolutely NO white areas.
That can also cause your map to crash.
You can have a colour that's close to white on the scale but it can't be flat out white if that makes any sense.
Well,
You can probably just darken the areas where you have the white parts if you have it on a different layer ( ? )
I did something like that, like brought the white down a bit so it was slightly dark then the flat out white and it seemed to work just fine c: