Client opens in Login window after single sign on


I’m running the Win client 2.6.1 stable and want to connect to a service (surfdrive) that I need to access through our university’s single sign on page. Now the login page pops up (as expected) and I can log in, BUT the client does not take over the authentification but stays in the login popup window and uses the HTML functionality there to show the client.

Weird enough, the very first login during the “create account” step worked for me and everything was working perfectly.

Any ideas?

Has anybody an idea???