Application ID is incorrect when EU used but US works fine

I am adding a login function to my flutter app and when using the Application ID from my backendless project which is an EU one it says its invalid, when i create a US backendless project and use its Application ID and API keys all works fine instantly. Why is this and is this expected? Thanks

Hi Connor,

This behavior occurs because the endpoint URLs for the EU and the US clusters are different. The SDK uses the US endpoint URL by default and needs to be set explicitly when used with the EU cluster.

Please see step #6 here: Client-side Setup - Backendless SDK for Flutter API Documentation

Regards,
Mark