In order to successfully make a payment, you must disable all popup blockers.
When you get to the Verify Payment Information window and click the Continue button, a new tab should open to display the Authorize.net credit card payment form. If this new tab does not open, a popup blocker is preventing the payment form tab from opening.
NOTICE: Do NOT click the Back button on the Verify Payment Information window.
Doing so will not take you "back" but will bring up an old payment form that we no longer use, and which will not work. We are working with our vendor to correct this issue.