Links not working

Hey @tigroumeow
I used this plugin for link thumbnail image to some other link rather than just pop up an image. Initially i was working fine but now it’s not working. Can you help me with this. I used this plugin before as well on linked page (https://hunterpp.com.au/product/search-more-footwear/) and when you click on footwear image (thumbnail image) was going to linked page (https://www.dropbox.com/s/fe53avpmxioqmzt/Hunter%20Promotional%20Products%20Footwear%20Catalogue%202020.pdf?dl=0)
But now it’s not going on linked page.

Thanks

The page I need help with: [log in to see the link]