Featured Sliders disapeared for unknown reason

Hi all, I'm using Clean Journal Pro theme for some years now - including a "Featured Image Slider" rotating some images on the homepage. For whatever reason the slider is not shown any more although it's still set up in the Customizer. It tried set up some other slider type, non of them is working and I have no clue what happened. I noticed the <section id="feature-slider"> is missing on my site but why? Can any one help me bring the featured image slider back? Thank you!