RTDE BrokenPipeError on rtde_client.send(data_object) after communication pause

I use RTDE python code to communicate with the URsim simulation tool in the VirtualBox
When I send command by command with short pauses - everything goes smoothly
But if I make two minute pause between consecutive rtde_client.send(data_object) - communication fails with the

rtde.py", line 267, in __sendall
    self.__sock.sendall(buf)
BrokenPipeError: [Errno 32] Broken pipe

error.

How should I connect to avoid this error?