We have about 20 iPhones in the company and yesterday all of them stopped connecting to Exchange via 3G. (Although they will still connect via wireless if the SSL is turned off.) The Windows Mobile phones continue to work properly. We have Exchange Enterprise 2003 on Windows 2003 Standard Servers with a front-end, back-end configuration. So OWA sits on the front-end server and that's the address used when configuring email on phones. I've checked with our firewall guy and nothing was changed there. I've made no changes to the Exchange servers. AT&T and Apple deny any changes from their ends, any ideas? We've never had any problems with this connection.