The site was throwing up ‘500 internal server error’ and the following error appeared in the apache error logs.
FastCGI: incomplete headers (0 bytes) received from server “/home/httpd/vhosts/default/fcgi-bin/phpfcgi”
If you are getting this error then it means that no headers are being returned when a request gets through to dispatch.fcgi
Possible reasons (and solutions) for this error are:
Session files are not configured correctly – This usually happens when moving between different server types. Delete the sessions in your /tmp folder. Execute the following command and try again.
killall -usr1 dispatch.fcgi
Missing AddHandler – The error occurs when the AddHandler given below is missing from httpd.conf AND and the user doesn’t have it in his app’s .htaccess either.
AddHandler fastcgi-script .fcgi