This message may indicate that a network problem has occurred, please check the following :

1- Check the IP address of the server you are trying to access. The IP address (private or public) set on your client must match the IP address of your server. It is advisable to have a static IP address set on the server to avoid the automatic change of the address that can occur when using DHCP. If you are trying to connect from a remote location using the public IP address, make sure that you have a static public IP address. Contact your Internet service provider for more information on this feature. It is also possible to use services DynDns to avoid this trouble.

2- Check your firewall settings. By default, inbound and outbound connections on TCP port 3389 must be enabled. Firewalls can be located in various places such as your Internet connection router, your windows firewall, or firewall/antivirus software.

3- If you are trying to connect from a remote location, a redirection (or port forwarding) rule must be activated on your router.

4- Antivirus software can sometime block Remote Access connections. To avoid this, place an exclusion rule on the following folder :

                 - C:\Program Files (x86)\TSPlus

                 - C:\wsession

5 - With the AdminTool, verify the status of your TSplus license. It is important to know if your issue is related to a TSplus license or to a Windows system problem.
If your current TSplus license is invalid you will need to install the latest TSplus update and activate a new valid license.