Hi, I have installed the official Mavericks release (update from Lion) on my MB Pro (2011). I can't sign in into FaceTime or iMessage (it tries for more than a minute, then I get an error message). Other iCloud functions work perfectly (mail, calendar, docs...). Many online proposed fixes date back from Mavericks previews... I tried those unsuccessfully: - Changing my iCloud password. - Ensuring time and date are automatically set - Editing the "hosts" file - Changing my DNS to 22.214.171.124 - Resetting iCloud docs (on iCloud.com) - Repairing permissions - Connecting from another place (other ISP, router) - In iMessage, signing in from "Preferences>Accounts" - Signing in with a "@icloud.com" alias (my .mac address is still my iCloud login/Apple ID). NONE of the above worked Any idea will be welcome!