After a update_versions in DirectAdmin I got this error on a sites error log:
[client 1.2.3.4:62903] AH01071: Got error 'Primary script unknown\n'
The URL it self gave:
File not found.
Yesterday everything was working fine. After updating Apache 2.4.x and PHP-FPM (5.6) I figured it had to do something with those services.
But the app (CodeEgniter) was running in a subfolder. The main folder contained a WordPress install and was working fine.
So after some time I tried to play with the .htaccess file, and I succeeded. I changed this old .htaccess:
RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^(.*)$ index.php/$1 [L] RewriteBase /fc2/
To this new variation:
RewriteBase /fc2/ RewriteRule ^index\.php$ - [L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . /fc2/index.php [L]
Don’t ask me why, but the Primary script unknown is gone.
So in this case it had nothing to do with ProxyHandler, ProxyPass or other configuration issues between PHP-FPM and Apache. Just a little .htaccess error which results in a bug.