We would like to mention that due to regulations in our home country we can not use PayPal yet. So we are using a less efficient but secure 3rd party payment solution to get payments via credit cards. Apparently the security parameters for credit card transactions in our country are set too high. That causes some transaction failures with some US customers. (We see no issues in EU and Asia). So if you are an US customer and face such an issue please retry doing the payment after a while. Due to timeout settings sometimes 2 or 3 times should be tried. In worst case you may need to communicate with credit card company. Please note that debit cards are also acceptable. Meanwhile we are working heavily to find other payment alternatives.