KimonoLab

You need to add tax details in: International > Taxes Add your tax rate(s) there, and then add them to a tax rule. The tax rule calculates and adds them to the order based on the customer's address. You also need to select "Display tax in the shopping cart" on the main taxes page for taxes to calculate. (You stated that it shows up in the cart, so that last part is for lurkers.) There's a possibility that the tax rule isn't set up properly, such as if the order was placed in Belgium, but the tax rule only has one country listed as a taxable location. You need to add every taxable location in the tax rule in order for it to be taxed after the person adds their address.

So, I ran a couple online stores with PrestaShop back in the day, and I remember there being many problems with getting taxes to function properly. I fixed the tax problems back then, and it looks like these are new ones, or that PS made the problems permanent and unfixable. Does anyone know how to: 1. Have the cart not add tax until after the customer inputs their address (so it adds taxes only if the customer's order is taxable). 2. Have multiple options for taxes (such as taxes in specific states and specific countries, and not for anyone else). Currently, I can only have it so tax displays for everyone but disappears after the customer inputs their non-taxable address, or not have any taxes on my website at all.

Look at: International > Taxes And see if "Display tax in the shopping cart" is enabled. Also, look to see if you have selected the applicable tax on the product itself. I think there are many problems with PrestaShop and taxes, so these might not fix your problem. For me, tax never showed up unless if I selected the tax rate on every product and then also selected the "Display tax in the shopping cart" option.