When trying to set up my CodeIgniter project on an Abyss Web Server, for some reason, accessing /index.php/controller1 only ever produces the default module as configured in the routes.php file.
After some fiddling around, here’s how I fixed it.
- Open the Abyss Web Server Console 
http://127.0.0.1:9999/ - Select Configure on the host you wish to configure
 - Select Scripting Parameters
 - Under Interpreters, click on the pencil icon to edit the line that refers to the PHP interpreter.
 - Set Type to Standard rather than PHP Style.
 
Restart the server and things should work properly now.