I had been struggling with “Session is down” errors during multiprocessing on my .NET project. The library I had been using was SharpSSH.
It is a known issue about SharpSSH. This library is no longer being updated. In order to get rid of this tedious error, I suggest you using another SSH librarry such as SSH.NET
It is easy to use. An example:
SshClient sshobject = new SshClient(OSShostIP, OSSusername, OSSpassword);
sshobject.Connect();
sshobject.RunCommand("mkdir /home/nedim");
sshobject.Disconnect();