Can't change background to white using Saber
So I'm making a video using this template https://www.youtube.com/watch?v=4DYNwi4oVP8&t=7s&ab_channel=RKMFX which is basically a firey logo intro using Saber.
I want to make two versions, one black background and one white.
Because the default is black there's no problem making that one. But for the white one, when I change the background layer(BG) to white it covers the Saber effect. I couldn't figure out why (I'm completely new to Saber). (In the screenshot I hide the BG layer so you can see what it should look like) 
I even tried making an empty white video and use it as background. It works in preview, but when I export the background is still black. Could someone help me? Thanks so much!


Here are the Saber settings. I only changed the color.
