TTMSFMXCloudFirebaseObjectDatabase Demo Application

Hello. When I try to run the firebase demo app it gives a browser error after clicking connect button. I've already set FAppkey, FAppSecret and FAppDatabase values. After clicking the connect button it take me into browser for google login section I guess. But in the page that is displayed it says :
Access denied: Authorization error. I don't know how to overcome this problem. It would be awesome to get some help. Thanks in advance

Can you please make sure you've entered a local callback URL in the Google developer console and assigned the identical value to the App.CallBackUrl property?

TMSFMXCloudFirebaseObjectDatabase1.App.CallBackURL := '';