Why are all the short messages suddenly gone and there is no automatic deletion setting?

It may be that there are some applications in your system that interfere with the normal operation of the system, especially some programs that have obtained root permission. For the safety of the mobile phone system, please do not use root permission at will. It is recommended that you back up your data, and clear all data when you enter recovery (turn off the phone, press and hold the volume up+power on button to enter recovery). When you resume data, don't restore the settings and third-party security software in your mobile phone for the time being. See if you can get back to normal.