Apple's mobile phone suddenly can't forward text messages. What happened?

I have encountered the same problem, and I just handled it normally yesterday. The response to the related posts on the 2nd floor of Apple official website Community is effective. The process is more troublesome, and the key is that it cannot be directly backed up after recovery, otherwise the problem will remain. Details are as follows:

1. Use the cloud to back up your most important things such as Address Book, that is, select icloud in Settings to open Address Book for backup.

2. Connect your phone to your computer and start iTunes to back up your phone synchronously.

3. Clear all contents and settings in Settings-General-Restore.

4. Reset the phone after "Reset".

5. Connect the computer. When iTunes finds the phone, don't check "Backup", but choose "Reset the phone". Of course, the "ID" and email address of the mobile phone are still your original ones.

6. After completing the above operations, click "iiphone" on the top right of the computer "iTunes" and select "Application" to install the application you originally downloaded. The rest, such as "ringtone", "music" and "movie", are all operated in the same way and do not need "information", otherwise the same problem will appear again. "Address Book" will be automatically restored to your mobile phone through "cloud backup". "MMS" and so on need to be reset.

7. The Application can also be downloaded and installed again.

8. After handling, everything is normal.