When attempting to log into ICloud for first time ever you get this error. Caused by Apple's 3 ICloud account creation limit per device. com.apple.appleaccount error 403 is the "best guess" error presented by IOS 7 when it see's the 3 user creation limit is reached and you attempt to create a new ICloud account by logging into ICloud on phone that has used all 3 account creation limit set by Apple. Fix: go to a different Apple device that has not burned up its 3 per device ICloud account creations and setup the account there. NOTE: you will use up one of the 3 maximum ICloud account creations on the device you use.