Characteristics issues!

You need to add the characteristics at the same time so that HikaShop can generate the variants.

You should:
1. Delete all the variants of the product on the listing of variants that you can access via the button "manage variants" on the product edition screen.
2. Delete the characteristics of the product.
3. Save the product.
4. Add the characteristics again.
5. The system will regenerate all the variants automatically and you should be able to see the dropdowns properly on the front end.

If you follow that procedure it should work.
Otherwise, delete that product and recreate it with the correct characteristics and it will work.

When you add characteristics to a product, the system has to generate one variant per combination of values.
So if you have 20 values for each characteristic of your product, that will mean 20*20*20 variants. 800 variants is too much to handle for your server and it stops its processing.

This often means that you're not using the correct tool for the job.
Instead of characteristics, you might want to consider options or custom item fields for at least some of the characteristics.
Each feature is designed to different cases. Variants/Charactersitics can be used when you want one variant per combination, so that you can set a price or an image, or a file, etc for each variant of the product. Options are other products which can be added together with the main product. Custom fields, allow the user to select things or enter information, but doesn't influence the prices.
Only the characteristics requires lot of resources if you have main values/characteristics for your product because it has to handle 1 variant per combination, which iw not the case with options of custom item fields:
www.hikashop.com/en/support/documentatio...ct-form.html#options
www.hikashop.com/en/support/documentatio...p-field-listing.html