Hi Ravi,

This module is not updated to Mendix 7.13. You can file a support ticket to Mendix to do this, in the meantime you can replace the this part of the code with this:

	public static void mail(final SMTPConfiguration configuration, String htmlmsg, 
			String plainmsg, final String subject, final List<String> to, final List<String> cc, 
			final List<String> bcc, IContext context, final List<IMendixObject> attachments,
			final Map<String, String> headers) throws CoreException 
	{
		final Message message = new Message();
		message.setPlainBody(plainmsg);
		message.setHtmlBody(htmlmsg);
		
		final Sender sender = new Sender(context);
		
		new Thread(new Runnable() {
		    public void run() {
				try {
					sender.send(configuration, message, subject, to, cc, bcc, attachments, headers);
				} catch (Exception e) {
					Core.getLogger("smtp").error("Error sending mail", e);
				}
		    }
		}).start();
	}
}