Gallery Slider not showing on Product page

I have set up the Variation Images Gallery for WooCommerce plugin on my local system, created a variation product, and confirmed that it works properly with gallery images and variations. However, after setting up the same plugin on the client’s site—which has many variable products with size and color attributes—I encountered an issue. When changing the color, the gallery images do not appear, and upon inspecting the page, I see a blank <div> in the slider. Could you help me identify the issue and suggest a solution to fix it?
Thanks.

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