You may have followed our Adyen HPP Setup guide here; however, when you are testing if the payment gateway works at checkout, you may have seen this error:
Here’s what you can do to resolve this error:
1. Make another run-through in our setup guide here and make sure that you did not miss a step.
2. Make sure that the credentials that you have placed on the plugin’s settings are correct.
Navigate from WooCommerce > Settings > Payments > AG Adyen HPP > Manage and double-check the Adyen Merchant Account, Skin Code, and HMAC Key. are all correct