So the host saying 'Socket closed'; [18 Jun 2019 17:54:10,558] WARN AbstractTransmitter | Error Sending message. Closing Connection. java.net.SocketException: Socket closed A "socket closed" error means that the connection has been terminated, however, no specific reason was provided/returned. The "socket closed" error indicates that the connection was lost outside of the control or awareness of the Driver. There can be a number of reasons for that, for example: network failure firewall timeout account permissions So, I could be wrong here.. But this says to me, the Host says "hey client?", the client doesn't respond, so the host closes the connection/socket. So, I'd start by checking to two problem clients, ensure they do not have anything like a firewall or security suite, permission system denying the traffic inbound/outbound via the application.