Codeigniter - 404 Page Not Found

php .htaccess codeigniter model-view-controller http-status-code-404

Since you have defined base url as

$config['base_url'] = 'http://localhost/etalasekursusci/';

Please try url http://localhost/etalasekursusci/user_authentication without index.php

OR Define base_url in config as below with index.php

$config['base_url'] = 'http://localhost/etalasekursusci/index.php';

Please post controller code, If you can.

php .htaccess codeigniter model-view-controller http-status-code-404

In Codeigniter 3 your class names must start with an uppercase letter as should their filename.

You should try rename user_authentication.php to User_authentication.php and change the opening lines to:

<?phpclass User_authentication extends CI_Controller {

similarly, the user.php should be changed to User.php and its opening lines to:

<?phpclass User extends CI_Controller {

The class documentation explaining this can be found here