New block when adding to cart

In the demos (https://simple.oceanwp.org/, https://lingerie.oceanwp.org/, https://store.oceanwp.org/), when adding a product a new block is displayed at the top of the screen indicating the product added and a view cart button.

However, on my web site, there’s just a text View Cart (“Voir le panier” in French) added next to the button Add to cart (“Ajouter au panier”).
Anyone would know how to get the block at the top ?

Thanks.

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