elementor slider does not show sometimes

Hi Guys,

In a website I built the elementor slider does not show now. Strange but true. There have been some updates. So maybe there is a problem between page build up and Elementor. Now i gave the background an image like one of the slides. But in the design environment I can't get the height visually right. It sits behind the slider and displays partly under the slider. Could you pleas look at this site how I can do it right. Maybe use a different solution.

I suppose it's more of an Elementor issue but I find your help most of the time better. Furthermore it's a strange thing it now does not show.
It's this homepage https://www.1zijninpraktijk.nl/

I hope you can help me. Thanks in advance!
Greets,
Jos