When I went from a standard Linksys router to the built-in router/modem that AT&T uses, I have been having trouble with email. I started to notice it with my cellphone if I were to send an email while connected to wifi I'd get an error saying failed to send message. At first I thought it was the app, so after taking it off several times and then trying to send mail connected to 3G, I realized it has to be the router. Then I started to have weird issues with my iPad and email, so after restoring it and updating, I'm totally convinced it's the router. Any ideas? I can receive email just fine.