Enabling the Timeout Idle Connections feature of the SOS Server prevents more than one user from connecting at a time. If that feature is enabled, once one user connects, if a second user tries to connect, both get disconnected.
To prevent this from happening, start the Server Manager, go to the General Settings tab, and disable Idle Connections. Then restart the SOS Service.
This will be fixed in 4.0.1
4.0 BUG: Timeout Idle Connections causes client disconnects
Moderator: SourceGear