Configuration of Docker swarm on Lin/Win machine

Hi All,
I did an hardware partition for installing windows 10 pro and ubuntu last version. My aim is to deploy an app. For doing that I started up a swarm on ubuntu and then I wanted to add the windows machine into the swarm as worker. Nevertheless, after opening the ports on both nodes, at the command “docker swarm join” I got this error:
Error response from daemon: rpc error: code = Unavailable desc = grpc: the connection is unavailable
Any suggestions?

Thanks in advance