How can I tell the reason why a transaction declined?

We display the errors based on the gateway response so each error will be different depending on the Gateway you're using.

So see the error, check the Contact Log for the contact used to submit the Form and click on it to open up the Form Fillout entry. Scroll down to the bottom of the submission data and you should see a numeric error code. You can look up your gateway name and the error code number online to find out what it means.

Also, you can contact Support. They can look up what we sent to the gateway via the Form submission and the gateway's full response.