I checked my Nginx log files and saw a lot of errors as below: *11047 FastCGI sent in stderr: “PHP message: PHP Warning: Parameter 1 to W3_Plugin_TotalCache::ob_callback() expected to be a reference, value given in /home/users/yinfor.com/wp-includes/functions.php on line 3597” while reading response header from upstream, I googled it and foundContinue Reading