when someone save a survey without fill the email adress (only user and psw), then the survey is saved but:
1. this message is visualized:
Invalid address: Error: Email failed, this may indicate a PHP Mail Setup problem on your server. Your survey details have still been saved, however you will not get an email with the details. You should note the "name" and "password" you just used for future reference.
2. if you try to resume the survey (from the link in the first mail received or in the resume form putting user and psw) most times you can't and it is only visualized the text introduction of the survey.