C# SSH.NET "ERROR: An established connection was aborted by the server"

I'm trying to connect to a server thru SSH.NET. It worked fine before but started to show "An established connection was aborted by the server" after some FW update on the server. Below is the code I'm using

private void HandleKeyEvent(object sender, AuthenticationPromptEventArgs e)
        {
            foreach (AuthenticationPrompt prompt in e.Prompts)
            {
                if (prompt.Request.IndexOf("Password:", StringComparison.InvariantCultureIgnoreCase) != -1)
                {
                    prompt.Response = "password";
                }
            }
        }
private void sshConnectBut_Click(object sender, EventArgs e)
        {
            var auth1 = new PasswordAuthenticationMethod("username", "password");
            var auth2 = new KeyboardInteractiveAuthenticationMethod("username");
            auth2.AuthenticationPrompt += new EventHandler<AuthenticationPromptEventArgs>(HandleKeyEvent);
            ConnectionInfo conInfo = new ConnectionInfo("Host", 22, "username", auth1, auth2);                
            
            this.sshClient = new SshClient(conInfo);
            this.sshClient.ConnectionInfo.Timeout = TimeSpan.FromSeconds(120);
            
            this.sshClient.Connect();   **<---- Error happened here**
        }

Can anyone help me on this issue please?

Il report non indica alcun file del repository né alcun test; inizia esaminando la configurazione di ConnectionInfo e il fallimento in sshClient.Connect(). Usa il thread dei commenti per stabilire se la modifica del firewall, i metodi di autenticazione o la disconnessione lato server sono riproducibili, quindi documenta una causa confermata e un test di regressione o una riproduzione minima.