I can not send from my yahoo mail-address. When I try to send a message is says "Outgoing Server '(null)' failed."

I have also found this at apple.com
http://discussions.apple.com/message...sageID=5840709

I made the settings by using the mail-assistent.
I do receive e-mail (via push)!

Any solution for it?

P.S. I'm on 1.1.4