1) If you found this error occurred, unplug network cable immediately from target PC. You can see this error in eventlog of Agentmap server side, but no error was recorded to client PC side.
If you want to see it by Agentmap log, please enable Agentmap log option.(It needs service restart of Agentmap.)
2) If there is no available port in Agentmap server side, you need to restart Agentmap server service from management tool menu.
3) Then, confirm Environment.ini in target client PC.
You can see Environment.ini in each windows users profile. So please confirm windows user ID beforehand.
Port number should be incorrect.
[Note]
This error message has been applied from Agentmap 4.1.2.6.
If you are using 4.1.2.0, and got invalid packet from PC, your Agentmap server generated huge size log, and Agentmap server service would down immediately.
Unless you remove target PC from network, agentmap server service cannot starts up again.