The Apple ID of 1. downloaded software is different from the Apple ID of the currently bound host, so it cannot be updated.
2. Program errors caused by jailbreak, abnormal display and blocked function.
3. Mobile phone hardware problems.
4. Number four. The Apple ID was seized.
Solution:
1. Delete the downloaded software and download the software again with the current account.
2. Update the firmware and brush it back to the genuine system.
3. Replace the whole machine. During the warranty period of Bank of China and Hong Kong Bank, non-man-made damage can be replaced after Apple's sale, and the rest will be paid.
4. Re-register an Apple ID.