Filter issue – Simple vs Variable Product!

i have tried your filter not working guide but the issue remains gthe same.

when i upload variable products, the filter works perfectly, but for simple products, thou the filter detects the attribute “silver” but still it doesnt show the products.

in the above link, all products are simple products and silver filter is being displayed, but when i click on silver filter it displays blank.

this is the link thats appended:

https://tuljabhavanijewels.com/shop/?filter_metal=silver

but when i change the link to

https://tuljabhavanijewels.com/shop/?pa_metal=silver

it starts working but then the silver filter isnt clicked. needed help in rectifying the issue.

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