In order to send emails through RDB you will need to have set up your mail service. To do this:
Double-click the RDB Pronet icon on the desktop to open it up.
On the Ribbon, click Options and then click User preferences.
Click Mail Service from the menu to the left of the window.
Complete all the fields. If you don't have the information required (server, port, username, password etc) your mail provider or IT contact will be able to provide them.
Click Save and Close.