Codeigniter blank page and error 500 in apache log?

I finally found something that pointed me in the right direction. These two posts mentioned how CI uses the @ in the database module might be causing that issue.

php return 500 error but no error log
CodeIgniter project loads blank webpage

I disabled auto-loading the database module and the site works. Now I just have to figure out the database error I was getting that might be causing CI to fail. I'll update this answer once I figure it out.

Update: I checked the account/password and access for the database everything was working. The issue was the php mysql driver was not installed. This is my first time really using an Ubuntu system and I thought that the mysql driver would be installed with the default php package, which I was incorrect about.

After installing php5-mysqlnd and enabling the database library in CI's autoload everything works properly now. The fact that I was not getting any errors is really making me consider changing frameworks.

Posting this, just in case it helps somebody...

If you are on a shared hosting platform and do not have access to directories other than where you are supposed to host your files: the trick was to force php to throw all errors even if apache could not.

Open "index.php" that resides in the root folder of your codeigniter installation;

define('ENVIRONMENT', 'development');if (defined('ENVIRONMENT')){    switch (ENVIRONMENT)        {            case 'development':            error_reporting(E_ALL);            /*added line below*/            ini_set('display_errors', '1');            break;......

Making the above change immediately started displaying what was wrong with the code and I was able to fix it and get it up and running.

Don't forget to set your codeigniter environment to "production" once you're done fixing it.

Here is another reason why errors might not be visible:

I had the same issue. In my case, I had copied the source from a production environment. Hence the ENVIRONMENT variable defined in index.php was set to 'production'. This caused error_reporting to be set to 0 (no logging). Just set it to 'development' and you should start seeing error messages in apache log.

Turned out the 500 was due to a semi colon missing in database config :-)