You should enter an HTML and plain text version of your message. Many people don`t allow HTML.
Use variables (between braces) if applicable to personalise. You should ALWAYS include the subscribe option "{unsubscribe}". With the
HTML message it must be as a hyperlink as follows:
Click <a href="{unsubscribe}">here</a> to unsubscribe.
Note: For bigger textareas, click the crosshairs, top right, in the textarea boxes.
Clicking the 'Preview' option for HTM loads a preview window in an iframe.