If you’re experiencing this error from the error log – “N:-5003: The order already exists in the database. The order has the same Order ID, so it will not be processed – merchant must generate new payment URL with a new invoice id, and this should allow the transaction to go through.”, this is due to the fact that most of the payment systems require every orders ID to have a unique value, this includes Authipay’s payment system. This error message means that you cannot pass over a multiple instances of orders with the same IDs.
As a workaround, you can use a third-party plugin called Custom Order Numbers for WooCommerce, this plugin can let you change the order ID to a much higher order ID which should be able to resolve the issue as the numbers will be assigned to new orders automatically. Please take note that this is a third-party plugin and you will need to contact Tyche Softwares‘s support if you need assistance or clarification with their plugin’s functionalities.
Furthermore, feel free to let us know if you need assistance with our plugin or if this issue persists for your site and our support team will be glad to help you with it.