I have a new iPhone 6 which was set up via a restore from an encrypted backup of my former iPhone 4S. The following has happened several times now...I will go into the iPhone Settings-->iCloud, and tap on the iCloud account at the top, and of course will be prompted for my iCloud ID password. I enter it, and after trying to verify for a while, the iPhone reports that the password is incorrect. BUT, I can sign into iCloud.com using the same iCloud ID/password combination, so the password is clearly NOT incorrect (and yes, I tried it several times to make sure I wasn't guilty of clumsy fingers). When the iPhone is in this state, people who send me messages from iPhones get the blue bubble, so I know that iMessages is successfully using the ID. But, if I sign into iCloud.com and look at Find my iPhone, it will say the device is offline, and the location given will be the "last known" location (typically a few hours before), and I am unable to have the phone "pinged." The first time this happened, I changed the iCloud ID password and that fixed things. The next time it happened I did nothing but power down and reboot the phone, and then things were fine. Any thought about what's going on and what I might do about it? It's as if the phone disconnects itself from iCloud, sort of, and can't sign back in without a system reboot.