Setting up OAuth 2.0 - What does this error mean: An error occurred on the server. Always include the following error reference when you report this error: [error not saved]

This article is part of the article serie Setting up OAuth 2.0 - Introduction

The error will occur when a migration has taken place by which the environment has been transferred to a different cluster. When determining the cluster within the API integration there is a hardcoded reference to the previous cluster.

Explanation:
After a succesful login a parameter containing the cluster will be returned. The cluster is not fixed and should therefore be treated as a dynamic value. In all the endpoints that are used, after a successful login, the first part of the URL should be used as the cluster.

Determining the correct cluster:
Send the acces token to the access token validation endpoint to receive the correct cluster:
https://login.twinfield.com/auth/authentication/connect/accesstokenvalidation?token=81d31b384cb8ac987ac6944d4eb99484