PHPLists might be running in Test Mode.
This is relevant only to domains hosted through http://cp.blacknight.com and if you have installed PHPLists through the "Application Vault"
To change out of Test Mode you will need to edit your config.php file. You can find your config.php file in the following location:
Where *$ID* is your installation ID, the number to the left of the install name in the Application Vault.
In this file you can find the line:
and change it to:
To get out of test mode for PHP Lists