Configuration
Configuration settings are changed in the preferences menu. This can be accessed from the file menu.

General
HTML in Email Body
Enables the use of HTML tags in the body of a message. Required for inline attachments. HTML in Email Body is enabled by default.
Timeout
Sets the maximum allowed inactivity time of a connection in seconds. Timeout is set to 8 seconds by default.
Max Retries
Sets the maximum number of number of attempts to be made should the initial connection fail. Max retries is set at 2 by default.
Delay
Sets the pause in seconds between each message. Delay is set to 0 by default.
External SMTP Server
Enabled
Enables the use of an external simple mail transfer protocol server. Disabled by default. For optimal mailing, it is recommended that SMTP with a reverse DNS lookup record be used.
Username
The username used to access the SMTP server.
Password
The password used to access the SMTP server.