Dynamic Zoom crops and create black edges

Hello.
I am trying to use the Dynamic Zoom function in Resolve 15, but when I hit play, it creates big black edges around the imagine, now matter where I put the green and red boxes. Have anybody any experience with this? I am following all the guides I have found on the web without any help...
Some photos to illustrate the problem:
I am trying to use the Dynamic Zoom function in Resolve 15, but when I hit play, it creates big black edges around the imagine, now matter where I put the green and red boxes. Have anybody any experience with this? I am following all the guides I have found on the web without any help...
Some photos to illustrate the problem: