Microsoft changed its CSP customer address validation API, as announced in this article.
As of this application version, the application is compliant with the updated address validation API. When an order is placed through UX1 for Customers, UX1 for Resellers, PCP v1, or RCP v1 for a customer account that has an incorrect postal address, an informative message is displayed, providing the user with detailed explanations.
Note: To learn how to validate postal addresses of customer accounts through the application's REST API, please refer to the Microsoft 365 Integration Guide >> Scenarios > Creating a Microsoft 365 Subscription and a New Microsoft Account.