In order to enable the Mail system you have to go under Settings -> Mail and fill ALL the following fields:

Username: the username for authentication

Email Address:

Password: the password for authentication

SMTP Host: Hostname of the SMTP server

SMTP Port: Port number of the SMTP server 

SMTP Secure: Security type for the connection (SSL, TSL, No secure)

Use SMTP: it is necessary to set it on TRUE. If false, the system doesn't use the SMTP server configured above.