My AppleID is an expired MobileMe account. So in iOS 5 beta, when I go to settings and turn on my iCloud account [let's call it firstname.lastname@example.org], my iPhone lets me. Everything works fine at first. However, when I open the Mail app, it warns me that my username/password combination is incorrect. I tried using a different AppleID that is a Gmail account and use it to register a new iCloud Me.com account. This new iCloud ID works in the Mail app and I can sent and received mails. [Let's call it email@example.com]. firstname.lastname@example.org also works fine on iCloud.com. Adding email@example.com as an iCloud account succeeds. I can use that account for Contacts sync and also for Find My iPhone. But using it for Mail or Calendar gives me the incorrect username/password error.. I have the same issue on iCloud.com, where my firstname.lastname@example.org account works for Find My iPhone and Contacts syncing. However, on iCloud.com (and also on iOS 5 and Mac OS X Lion), I cannot yet access the Mail and Calendar apps. I hope that Apple fixes this issue before the formal launch of iCloud. My question is this: is anyone else experiencing this and does anyone know of a way to fix this, so that I can use email@example.com as an e-mail address?