If using plain text to send the email: Select text/plain for the E-mail MIME type setting and specify the sensor default event mask ({sensor.default.event.mask}) for the Event mask setting.
If using HTML to send the email: Select text/html for the E-mail MIME type setting. For the Event mask setting you can either enter the sensor default event mask ({sensor.default.event.mask.html}), or you can enter HTML directly into this field. If doing the latter method, it is recommended to edit the HTML in a separate text editor and paste the value into the sensor, as the field is small.
You must be using service update SU30 or higher to use the {sensor.default.event.mask.html}.