I've been trying to set up an smtp mailer so that once a user fills in a form on my website it will automatically send the message via email to me. I have all the files of PHPmailer in the same directory but it keeps on giving me the above error whenever the form is submitted. 

This is line 1943 of PHPmailer.php :

```
throw new Exception($this->lang('authenticate'));

```

Does anyone know what the problem is ?

Thanks.