Problem with display attribute on frontend not load

Are you sure the variations exists? Sounds like the variations and attributes may not be set up correctly: https://docs.woocommerce.com/document/variable-product/

If they are though, then something on your site must be causing a conflict. Try temporarily switching back to the WordPress Twenty Sixteen Theme, or Storefront, and disable all plugins except for WooCommerce. If that resolves the issue, then slowly re-enable features until you find the one that’s causing the conflict.

Hello, yes all variations exist (here image on variations screenshot https://imgur.com/a/QcnFu ). I’ve just write above that i’ve just try to swich into defoult theme (Twenty Sixteen and also StoreFront) and disable all plugin but nothing change. Problme remain so is not any conflict.

Image with Twenty Sixteen https://imgur.com/a/pxNFk

I create a defoult combination https://imgur.com/a/HWCMj and in this case not work selection on attribute on front-end. If i not put any value on defoult combination if i select one value of first attribute (in my case “Supporto”) and then select value on last atribute (in my case “Composizione Plastificazione”) is not possible to retour on last select on first attribute “Supporto”.

Is very very strange. I have six attributes and are positioned in order. It seems that no interpreters woocommerce order and instead bring up the combination based on what I select in the attribute ordered at No. 3 to do it based on what I select with the number 5 attribute.

So is very very strange. I also try do downgrade version WordPress and WooCommerce (on localhost website) but nothing change.

I not be able to use my website becouse is not possibile to select the real variaiton combination.

Please, please, help me in this problem on woocommerce code (not theme or plugin).