When I try to reply to or forward an e-mail in my iphone's e-mail app, I get the following message:"A copy has been placed in your Outbox. The sender address (then it shows my e-mail address) was rejected by the server." I never had this problem with my iphone 4. I can send new e-mail messages, just can't forward or reply. I use Yahoo as my main e-mail client, but also have iCloud. The problem is the same with both.