Problem: The client is experiencing an error during checkout when using the MasterCard gateway plugin combined with WPML's multicurrency feature. Specifically, selecting certain Arab countries like Saudi Arabia triggers the error: "Object of class NyholmPsr7Request could not be converted to string". Solution: We investigated the issue and found that the error persists even without WPML, when using the same currency settings in WooCommerce and setting WordPress to Arabic. This indicates that the problem is not related to WPML but to the MasterCard gateway itself. We recommend contacting the support team of the MasterCard gateway to resolve this issue.
Please note that this solution might be outdated or not applicable to your specific case. If the problem persists, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If necessary, please open a new support ticket with us for further assistance at WPML support forum.
