In the "TPAMAdministratorManual.pdf" manual it says that if the "Maximum Simultaneous Sessions" attribute is set under the "PSM Details" tab, TPAM will allow for simultaneous PSM sessions for a single account.
We have set "Maximum Simultaneous Sessions" to 3. When the first user raises a PSM Request, he is able to do so successfully and the Windows screen is displayed. However, when the second user raises a request for the same account, the second user is able to see the Windows screen, but the first user gets a blank screen.
Terminal Service Configuration does not allow users to have multiple sessions.
In the Terminal Service Configuration tool you need to uncheck the "Restrict each user to a single session" check box.