I rebooted the server and the behavior changes a little.
The first time I connect to the server I get the KDE user login/pass screen. I log on and the session hangs/disconnects.
When I try to reconnect I get the behavior described in my first post.
Seems like the first session is somehow opened but I’m unable to use it neither reconnect to it later.
It seems to me similar to what another user described recently on the forum.