For cluster computing, all the compute nodes have to connect to the master node to read the required data and write partial data of the final results. This will establish the inbound connections of the master node.
For using the workstation version of Windows, like Windows 7/8/10, there is a limit for the number of inbound connections. On the other hand, the server version of Windows, like Windows Server /2012R2/2016, there is NO limit for inbound connections.
For Windows 7/8/10, the inbound connection limit is 20. If the established inbound connections meets the limit, there may be errors while Moldex3D parallel computing is launched. Therefore, we strongly recommend to install Windows Server for Master node.