I have installed latest nightly build (4.1.2.3) that you provided, the connection to the server failed, 

Here is the debug output to the command: 

x2go-INFO-1> "Starting X2Go Client 4.1.2.3..."
x2go-WARNING-1> English language requested, not loading translator.
x2go-WARNING-1> English language requested, not loading translator.
x2go-DEBUG-../src/onmainwindow.cpp:10867> Getting X.Org Server settings.
x2go-INFO-3> "Started X2Go Client."
x2go-DEBUG-../src/onmainwindow.cpp:626> "$HOME=C:/Users/teiny171950"
x2go-DEBUG-../src/onmainwindow.cpp:2349> Reading 1 sessions from config file.
x2go-DEBUG-../src/onmainwindow.cpp:13380> libssh not initialized yet. Initializing.
x2go-DEBUG-../src/pulsemanager.cpp:369> pulseaudio --version returned:"pulseaudio 13.0
"

x2go-DEBUG-../src/onmainwindow.cpp:10770> Starting helper servers for Windows ...
x2go-DEBUG-../src/onmainwindow.cpp:10937> "/cygdrive/C/Users/teiny171950/.x2go/var" cygwin var path
x2go-DEBUG-../src/onmainwindow.cpp:11025> "C:/Users/teiny171950/.x2go/etc/sshd_config created."
x2go-DEBUG-../src/onmainwindow.cpp:10432> Resolved localhost.
x2go-DEBUG-../src/onmainwindow.cpp:10454> Port is free: 7022
x2go-DEBUG-../src/onmainwindow.cpp:11376> Logging cygwin sshd to: "C:/Users/teiny171950/.x2go/sshLogs/p24388.log"
x2go-DEBUG-../src/onmainwindow.cpp:11390> Creating desktop: x2go_TEiny171950
x2go-DEBUG-../src/onmainwindow.cpp:10432> Resolved localhost.
x2go-DEBUG-../src/onmainwindow.cpp:10460> Port already in use: 7022
x2go-DEBUG-../src/onmainwindow.cpp:10432> Resolved localhost.
x2go-DEBUG-../src/onmainwindow.cpp:10460> Port already in use: 7022
x2go-DEBUG-../src/onmainwindow.cpp:11487> User mode OpenSSH server started successfully.
x2go-DEBUG-../src/pulsemanager.cpp:227> pulse started with arguments ("--exit-idle-time=-1", "-n", "-F", "C:\Users\teiny171950\.x2go\pulse\config.pa", "-p", "C:\Program Files (x86)\x2goclient\pulse\lib\pulse-13.0\modules", "--log-level=debug", "--verbose", "--log-target=file:C:\Users\teiny171950\.x2go\pulse\pulse.log") - waiting for it to finish...
x2go-DEBUG-../src/onmainwindow.cpp:2830> Creating QPixmap with session icon: '":/img/icons/128x128/x2gosession.png"'.
x2go-INFO-8> "Starting connection to server: dcilda927:22"
x2go-DEBUG-../src/onmainwindow.cpp:2931> Starting new ssh connection to server:"dcilda927":"22" krbLogin: false
x2go-DEBUG-../src/sshmasterconnection.cpp:168> SshMasterConnection, host "dcilda927"; port 22; user "e171950"; useproxy false; proxyserver ""; proxyport 22
x2go-DEBUG-../src/sshmasterconnection.cpp:248> Starting SSH connection without Kerberos authentication.
x2go-DEBUG-../src/sshmasterconnection.cpp:250> SshMasterConnection, instance SshMasterConnection(0x3cf9ad8)  created.
x2go-DEBUG-../src/sshmasterconnection.cpp:492> SshMasterConnection, instance SshMasterConnection(0x3cf9ad8)  entering thread.
x2go-DEBUG-../src/sshmasterconnection.cpp:573> Setting SSH directory to C:/Users/teiny171950/ssh
x2go-DEBUG-../src/sshmasterconnection.cpp:795> Session port before config file parse: 22
x2go-DEBUG-../src/sshmasterconnection.cpp:805> Session port after config file parse: 22
x2go-DEBUG-../src/sshmasterconnection.cpp:869> Session port before config file parse (part 2): 22
x2go-DEBUG-../src/sshmasterconnection.cpp:879> Session port after config file parse (part 2): 22
x2go-DEBUG-../src/sshmasterconnection.cpp:903> cserverAuth
x2go-DEBUG-../src/sshmasterconnection.cpp:942> state: 1

x2go-DEBUG-../src/sshmasterconnection.cpp:674> Setting SSH directory to C:/Users/teiny171950/ssh

Thanks for the support, 

Tamir