This is only relevant if you use CONTENIDO -Version version 4.9.13 or newer
CONTENIDO configures automaticly "SMTP" as transport type for your mails. But before it works, you have to configure the login informations at backend. Please go to the menu item "System" and "Configuration" to configure your SMTP mail server. If you do not want to use SMTP as mail transport type, you can choose alternatively "PHP mail".