I had the same problem, but mine occurred right after initial setup. Like you, I'm using my ISP email, in my case RoadRunner (AKA Time-Warner). I found out that some ISP's (like mine, and I suspect yours, too) will not allow you to send e-mail from a portable device. It has something to do with spam prevention. Check out my post over @ WMexperts that addresses this fix.
http://discussion.wmexperts.com/show...88#post1475688