Solve the problem of No Update Required when WordPress cannot log on to the background

The following error is reported when logging on to the background of wordpress:

No Update Required

Your WordPress database is already up-to-date!

No Update Required

The system is automatically upgraded.

 

Cause analysis:

1: check the email to confirm whether the wp has been automatically upgraded. If yes, it may be caused by incompatibility of the plug-in;
2: rename the wp-content folder, create a new folder as wp-content, and copy the template themes of the original folder to test whether you can log on to the background;
3: copy the original plugins file to test whether you can log on to the background;
4: Test the differences between the original folder and the current folder;
Solution:

1: I tested here because of the object-cache.php file, so rename the object-cache.php file.