Maybe this would be more clear:
Try this link:
Code:https://www.paypal.com/cgi-bin/webscr?cmd=_cart&upload=1&business=seller@designerfotos.com&item_name_1=Item Name 1&amount_1=1.00&item_name_2=Item Name 2&amount_2=2.00
Works like that, but if you change to "sandbox.paypal.com" it says "Server error".
Code:https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_cart&upload=1&business=seller@designerfotos.com&item_name_1=Item Name 1&amount_1=1.00&item_name_2=Item Name 2&amount_2=2.00
Is it an issue on their end or I am doing something wrong ?