iCloud sign in keeps popping out with the old email address
I changed my Apple ID but the iCloud sign in pops up every second with the old email address. Tried changing it through the iCloud setting but cannot signed in using the correct password on the old email it says Your Apple ID or password is incorrect. So whether i put the password for the old email it still fails. How can I get the correct Apple ID to my iPhone 6?
Also, it freezes my phone and can get to my messages nor make a phone call. Please HELP!!!
iPhone 6 Plus, iOS 8.1.1