Codeigniter 2 and tweeter integration

PHP
1

In Codeigniter(version 2.0): Twitter returns a user to

domain.com/connections/twitter/?oauth_token=UXrtdKuLS2N6TCUJdtQAB&oauth_verifier=UXrtdKuLSUXrtdKuLS2N6TCUJdtQAB2N6T

But I keep getting a 404 page. Am I missing something really simple yet important?

Note: Page becomes visible, if I refresh it after removing ‘?’ from the url.
$config[‘enable_query_strings’] is already enabled (set to TRUE).