The redirect URI in the request, https://www.ipdc.org.au/?option=com_slogin&task=check&plugin=google, does not match the ones authorized for the OAuth client. To update the authorized redirect URIs, visit: https://console.developers.google.com/apis/credentials/oauthclient/593314681082-fdjv0cm9dofr6610hbc20ar63fvle1ob.apps.googleusercontent.com?project=593314681082