The problem is more than likely PHP mail() which is underneath UE. As I posted in a different thread, if you are testing on a local machine and php.ini has the smtp set to localhost then you have to have a local mail server. If you point it to another mail server you will run into authentication issues. When you move it to production there will probably be a mail server installed. So the easiest way to manage this is to do as Tom suggest and use the production environment.