Credentials are not valid.

I have installed WooCommerce and the SumUp extension on a client’s website (WordPress 6.5). The SumUp plugin is up to date.

I have created the required oAuth element on the SumUp platform, and copied/pasted client ID and client secret in the application settings.

When I click on the save button, I receive an error message “Credentials are not valid. Please check and try again.”. On the dashboard, I have an other error message “SumUp Gateway is not configured properly.”

We tried to chat with the SumUp support team, but they can’t solve it.

Everything has been checked and rechecked, so I fear there is an issue with the plugin.

The page I need help with: [log in to see the link]