Cimplicity 8.2 Partner dead node

Hello,

I have a Cimplicity 8.2 project running in Windows 7 communicating with two redundant CRU320. Communication works correctly even changing from master to backup unit. Then I open the project in another pc with Cimplicity 8.2 and Windows 8.1 and it communicates correctly with plc but, from time to time, communication fails and status log shows the following message:

Partner Dead Node: [PC_NAME] Private Port: MAC_PTM

Any idea? Something to do with Windows Firewall?

Thank you

Andrea