Impossible to execute coupon code in cart or checkout when having more then one different products in the shopping cart. Reproduce: 1. make an auto generated coupon code that does a discount for the whole cart. Condition is that the subtotal minimum of x is met. 2. one single products to the cart and apply the coupon code --> this works just fine 3. now add a different product to the cart (the two products must be different sku) 4. apply the coupon code (iin the cart or the checkout; doesn't matter) 5. result: {"messages":{"error":[{"code":500,"message":"Server internal error. See details in report api\/571656540374" }]}}  