Forum User doesn't stay logged in
 

hi,

After upgrading from 3.8.3 to 4.0.1 i noticed that the users don't stay logged in the forum. Everytime I visit my forum I have to log in again.

And also when i log in it says successful log in but I don't seem to be logged in. when I click on a forum then I'm displayed as a logged in user.

Any idea?