iMessaging an iPhone from an iPad I am trying to iMessage an iPhone 4S using its phone number. When I press send, the sending progress runs to ~90% and pauses. Then, after about 1-2 minutes, a red exclamation point appears. This happens every time. My WiFi connection is great. What's the problem? I have a 16 GB iPad WiFi running iOS 5.
Why not try iPhone's email address? As far as I know, iMessage is registered by e-mail, not phone number.