How is this possible? App gets transparent

Hi, so I got a problem

I used a black to alpha gradient (png picture) and this happened.
It seems that the App became transparent where Ie placed the image gameobject.

This are the options of the sprite:

And this from the gameobject:

Source Image: sprite(gfx_gradient)

Color: (put the alpha to 206)

Material: None

Raycast Target: checked

Image Type: Simple

How can i fix this issue? I have no clue why this happens

Put an jpg under the png first, so the jpg will block the trasparency, i think, and you still will have the gradient effect…
or change the gradient from png to jpg…