The Unknown status indicates that the result of a payment attempt is unclear, and Stax Bill will pause billing on this customer until it is clarified by a user interaction. It indicates that the system is unsure of how the payment was ultimately resolved within the gateway after the request was made. This could be due to not receiving a response from the gateway (such as a response timeout) or the response received from the gateway wasn't a clear success or failure.
The status and hold prevent duplication of any collections from a customer and avoid potential billing problems. It does this by pausing billing automation on the customer and preventing any other actions on that customer until the unknown payment is resolved. Once resolved, billing will resume, and Stax Bill will catch up, one bill at a time.
From within Stax Bill, or through the API, a user in your account must manually resolve the payment as either successful or failed. If you go to the payments tab on the customer, you will see a payment with a status of 'Unknown.' If you click on the details of that unknown payment, you can manually mark it as successful or failed. If you log into your gateway and find this payment, you can see if it was successful or failed. If you cannot find the payment, that likely means the gateway never received it, and you should mark it as failed.