I have created one shopping cart rule with uses per coupon "1" and uses per customer "1". For example, if user A adds product in cart and apply "COUPON01" on cart page. Also user B adds product in cart and apply same coupon "COUPON01" on cart page. Both users click on the place order same time and redirect to PayUPayment gateway for payment. Now both users get discount with single coupon.
How can I fix this issue in magento.(It is the case of simultaneous request to avail single coupon)