Free SMTP server? [SOLVED]

I have some code that works great with Wifly, Arduino and Gmail. Unfortunately it gives me this error when I'm using T-Mobile Mifi only.

So I thought I'd try this: Using this method at the bottom of the page AUTH LOGIN

There must be an easier way. Unfortunately T-Mobile does not have it's own SMTP relay or server without authentication. Please help!

Do you think this might work without the same error GMail gives me?

There's only one way to find out! Unfortunately I have to climb a mountain to test it...

You can host your own mail server...

Unfortunately my PC does not have an external IP address. Sprint 3G.

SMTP2GO seems to work using Sprint. Next try T-Mobile!

Thanks for listening! Works with T-Mobile.