My friend has an iPhone 5c with AT&T. When he clicks on the App Store icon, there is a blank screen and the 1 minute later, it prompts him to sign in with his password. He says it is the CORRECT password, however it keeps prompting him to put in his password. He is able to log in to itune fine on his computer His version is 8.4.1 12H321 He has never updated the software, therefore I did last night and still same issue He does NOT have another itune account He does not have icloud set up. He does not have any apps other than email on the iphone. However, now he wants to download apps. Any help would be appreciated.