First, you should have a look to the article Overview of the software communication to understand that several communication steps might be involved in the error message.
Then please check the following points:
- Use the ping command to verify that the machines can communicate together,
- Disable firewalls of the involved computers (you will reestablish them once your error messages are fixed),
- Check the IP address for the IPSI Server Manager/IPSI Servers. If you installed IPSI on the same computer than MiddleVR, you just need to use "localhost" or "127.0.0.1" as address in MiddleVR,
- Check for conflicts with the port 5000 (for example, A.R.T.'s optical tracking systems use this port as default). If so, use the syntax "127.0.0.1:5001" in MiddleVR to set another port,
- Kill and restart the IPSI Service Manager. The executable is called "IPSI_SM_SERVER.exe". You may find it (to launch it later) in "Program Files\HAPTION\IPSI\Server Manager\V2\bin". Or simply reboot the computer...