Codeigniter Paypal notify url

Codeigniter Paypal notify url

I'm using paypal on a site based on Codeigniter. I set up the paypal form,
everything is working fine except the notify_url. It's not called at all.
The url is like this: www.mysite.com/callback If I change the url to a
simple php file like www.mysite.com/callback.php, which is not part of the
codeigniter framework, it's working fine. I tested the original callback
with the IPN simulator and it's working as well. The first line of the
callback is a logging function for testing but nothing happens. Any help
would be appreciated.