[solved] HTTP 500 error

Hello,
I installed the module and the XML rule for AUP and when I try to use this I just get an error. I fill in the paypal email and number of points to convert and upon clicking on the PayPal button I get a 500 (Internal Server Error) that he could not load the address http://<basic site address>/index.php/benutzer ... Strange thing is that if I try to enter this URL manually, it opens without problems - which should be, because that is the user detail menu.
No request email is sent to given custom address.
Do you have any idea what could be causing this?

Filip

Nope, what is exactly the url? (hide the domain name if you want)
Are you using any SEF other than the core Joomla SEF?

This is the URL: gravedeco.casaconsult.net/index.php/benutzer

I'm not sure what SEF exactly is and how do I get this information about my site...

I can not find the plugin on that page.
Try disabling SEF from the joomla configuration.

I disabled the System - SEF plugin in the Extension manager. I hope that is what you meant. But it is still giving the same error.
The plugin itself is located on the very bottom-right corner of the page.

No I meant in Joomla configuration page.

I can not see the module on that page. Provide me an account by mail with enough points if module requires to be logged in to show.