When an application is published within the admin tool as a unique application and assigned to a user or a group sometimes the session starts and logs off instantly.
The reason why is that the unique application once started is ending its own process and starting a new one, resulting in a log off because TSplus detects that no more applications are running for this user.

Solutions :
1- Open an admin tool and assign the remote desktop to you users or group as the only application for this user or group. The session will remain active once the application is started.
2- Open an admin tool and assign the remote taskbar or the floating panel to your user or group. The session will remain active once the application is started.