I'm trying to connect via SSH using putty but it closes the window.

Please read the putty documentation. I have never used it myself.

Hi Jafo:

I found the way to keep the window open, so it's sending this message: "Connection closed by remote host"

It was working OK until yesterday.

Just checked it, it is running fine. Make sure your firewall is not blocking it.

I restarted SSHD on that server just to be sure.

Thanks Jafo, now I can connect via SSH, but something similar is happening with communication in port 9091

Still having the same problem with port 9091.

Port 9091 is open and accepting connections.