WP /wp-admin/admin-ajax.php produces 404

Your /wp-admin/admin-ajax.php might have been modified by another php file or plugin. Try downloading a copy of your wordpress version and overwrite admin-ajax.php with the original source file.
If that doesn’t work, try deactivating your plugins (or theme) one by one until you notice a difference.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)