StartCameraFade doesn't work when called from UMG button press

When I make a button press in the level blueprint call StartCameraFade it works, but when I put the same blue print code in response to a UMG button press it ignores it. Any ideas?

I found this tutorial very helpful: HTF do I? Fade in and Out the Viewport ( UE4 ) - YouTube

It uses an image animation to create a fade to or from black that can play when you press a button. This is just the way I’ve done it.