Unable to add product quantity more than one items in one order MAGENTO

Question

I am facing a very strange problem in my magento site, the problem is when I am adding a quantity for a particular product from frontend for order it works properly for one item, but when I am adding one more different item in the same order and trying to increase its quantity it restricts to me the only 1 item for the next item, please suggest to me some ideas how I can fix this issue: http://www.debreiboerderij.nl.

Answer 1

Magento: limit product max quantity to 1 per order. quantity 2 = 2 orders