codeigniter PHP App on server. URL returns blank page

It mostly means that there is a php error. Try enabling debugging: <br> <br><pre>Note: By default, CodeIgniter displays all PHP errors. You might wish to change this behavior once your development is complete. You’ll find the error_reporting() function located at the top of your main index.php file. Disabling error reporting will NOT prevent log files from being written if there are errors.</pre> <br><a href=“http://ellislab.com/codeigniter/user-guide/general/errors.html”>http://ellislab.com/codeigniter/user-guide/general/errors.html</a>

Do both WordPress & your app need to be on the same subdomain? Why not put them on separate subdomains? Or have your app on the subdomain and WordPress as a subdirectory?

Hello,

There are two types of 500 errors, one is when you are using Apache and you have a configuration error, either in your .htaccess file or in your Apache config file.

The other type of a 500 error is the HTTP 500 error which you are experiencing. This means there is an issue with your Application. To properly debug this, you need to create an error log of your application and check out the error there. In your case you have used the PHP tag. This means you need to create an error log using php.ini or .user.ini file and indicate where the PHP error log is located. It’s possible the error log is already there somewhere as well. The best way is to check your PHP options.

This can be achieved by creating a info.php file in your Application’s path and typing in

<?php
phpinfo();

Then open the file in our browser. It will give you all the information you need about your PHP settings.