If you already have an ATPI membership, please login. You will be able to renew or change your membership from your account.
About 3D Secure: Some transaction will go through 3D Secure checks on this website. 3D Secure is provided by your bank, not ATPI, and is an extra layer of security for online transactions. If the 3D Secure popup shows and you have not received a message from your bank to confirm payment on your phone, please open your bank app to confirm.
For 3D Secure to work, you need to enable popups on the browser. After clicking the Register button, if nothing happens, please check your popup setting and enable it.