Symptom: some or all Agents are shown with a "Connection failed" status in the Coordinator application.
Solution: Please open the Agent Settings dialog on the Agent(s) having the "Connection failed" status. If you see a message box offering to open firewall ports, click 'Yes' and see if this fixes the problem.
In addition, check if Agents are connected to different sub-nets. If this is the case, you may need to open the IncrediBuild ports for the external sub-nets since these are opened to the Agents' sub-net only by default.
Please note that the Agents communicate between themselves by using port 31105. Please make sure that this port is opened on all Agents since this can also be a cause for the "Connection failed" status.