Error 404 Page Not Found When Updating a Post or Page

Help! All of a sudden my WordPress admin has started showing a ‘Error 404 Page Not Found’ message whenever I try to update an existing post or page on my site.

Creating new posts and pages works fine.

This happened suddenly last night when I was updating a series of posts and it suddenly started showing this message.

So far I have tried:

1. Settings > Permalinks Save button
2. Disabling all plugins
3. Updating all plugins
4. Changing theme
5. Deleting all WP content apart from wp-config.php and wp-content folder, and uploading fresh WordPress install
6. Updating WordPress

I’m not sure what else to try?

Updating Permalink changes update your permalinks settings and flush rewrite rules. In most cases this fixes the WordPress posts 404 error. BTW, you already tried this and I hpe your .htaccess should be writable. Have you checked it?

If not then you can change .htaccess file permission temporary writable by changing the permissions to 666 and make sure after after ‘Save Changes’ action turn back .htaccess permission.