FastCGI : 500 internal server error

Issue :

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”

Fix :

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