product carousel with products on sale shows nothing

Hi,,
I want to make a product carousel on my homepage. I succeeded with a normal product carousel (top one on the homepage) but at the bottom of the page I have made a product carousel with proudct filtered by On Sale. There are about 2- products I put on sale, but nothing is showing in the carousel. That there are products on sale is shown in the top carousel where at one of the products is the sign Uitverkoop, which is dutch for on sale.
How do I get the products in the second carousel visible? It should be below the pictures of the lady. The container is there.. the carousel is in the source, but nothing visible. Hope you can help out here.

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