It works fine for me using my mail server smtp.comcast.net <b>IF</b> I use a valid recipient (of course) AND <b>if the return address contains a valid domain</b>.
Using test@labviewprog.com fails because labviewprog.com is not a valid domain. It works with my correct return address or anything else with a valid domain. e.g. test@ni.com works. Try it! If you still have problems, it might be easiest to setup a packet sniffer (e.g. <a href="http://www.ethereal.com/";>ethereal</a>) to see the full communication and server messages.
