Package: x2goclient Version: 4.0.5.0-0 When trying to connect to a session using HTTP proxy, it fails the first time with the below message in an error dialog. "Socket error: disconnected" When connecting to the same session the second time within 30 secs, the connection goes through and I am logged into my virtual desktop. I am able to replicate this issue several times. Below is the output of the client running in debug mode (with the above scenario captured) - ========== x2go-INFO-8> "Starting connection to server: desktop.a1200.virtualorgs.net:80" x2go-DEBUG-../src/onmainwindow.cpp:2758> Starting new ssh connection to server:"desktop.a1200.virtualorgs.net":"80" krbLogin: false x2go-DEBUG-../src/sshmasterconnection.cpp:168> SshMasterConnection, host "desktop.a1200.virtualorgs.net"port 80user "superuser"useproxy trueproxyserver "desktop.a1200.virtualorgs.net"proxyport 80 x2go-DEBUG-../src/sshmasterconnection.cpp:205> Starting SSH connection without Kerberos authentication. x2go-DEBUG-../src/sshmasterconnection.cpp:209> SshMasterConnection, instance SshMasterConnection(0x10d8030) created. x2go-DEBUG-../src/sshmasterconnection.cpp:445> SshMasterConnection, instance SshMasterConnection(0x10d8030) entering thread. x2go-DEBUG-../src/sshmasterconnection.cpp:481> libssh not initialized yet. Initializing. x2go-DEBUG-../src/sshmasterconnection.cpp:559> Created HTTP proxy socket: -1 x2go-DEBUG-../src/sshmasterconnection.cpp:564> Connected to HTTP proxy server: "desktop.a1200.virtualorgs.net":80 x2go-DEBUG-../src/sshmasterconnection.cpp:581> "Cannot connect to desktop.a1200.virtualorgs.net:80" - "Socket error: disconnected" x2go-ERROR-2> "Connection error: Cannot connect to desktop.a1200.virtualorgs.net:80: Socket error: disconnected" x2go-DEBUG-../src/sshmasterconnection.cpp:711> SshMasterConnection, instance SshMasterConnection(0x10d8030) waiting for thread to finish. x2go-DEBUG-../src/sshmasterconnection.cpp:715> SshMasterConnection, instance SshMasterConnection(0x10d8030) thread finished. x2go-DEBUG-../src/sshmasterconnection.cpp:722> SshMasterConnection, instance SshMasterConnection(0x10d8030) finished destructor. x2go-INFO-8> "Starting connection to server: desktop.a1200.virtualorgs.net:80" x2go-DEBUG-../src/onmainwindow.cpp:2758> Starting new ssh connection to server:"desktop.a1200.virtualorgs.net":"80" krbLogin: false x2go-DEBUG-../src/sshmasterconnection.cpp:168> SshMasterConnection, host "desktop.a1200.virtualorgs.net"port 80user "superuser"useproxy trueproxyserver "desktop.a1200.virtualorgs.net"proxyport 80 x2go-DEBUG-../src/sshmasterconnection.cpp:205> Starting SSH connection without Kerberos authentication. x2go-DEBUG-../src/sshmasterconnection.cpp:209> SshMasterConnection, instance SshMasterConnection(0x10d3580) created. x2go-DEBUG-../src/sshmasterconnection.cpp:445> SshMasterConnection, instance SshMasterConnection(0x10d3580) entering thread. x2go-DEBUG-../src/sshmasterconnection.cpp:498> libssh already initialized. x2go-DEBUG-../src/sshmasterconnection.cpp:559> Created HTTP proxy socket: 13 x2go-DEBUG-../src/sshmasterconnection.cpp:564> Connected to HTTP proxy server: "desktop.a1200.virtualorgs.net":80 x2go-DEBUG-../src/sshmasterconnection.cpp:792> cserverAuth x2go-DEBUG-../src/sshmasterconnection.cpp:807> state: 1 x2go-DEBUG-../src/sshmasterconnection.cpp:966> Password authentication requested. x2go-DEBUG-../src/sshmasterconnection.cpp:657> User authentication OK. x2go-DEBUG-../src/onmainwindow.cpp:2853> SSH connection established. x2go-DEBUG-../src/onmainwindow.cpp:3120> Continue normal X2Go session ========== I am able to connect on the first try with the same HTTP proxy server settings using Putty and even NoMachine v3.5. But for X2GO, it's always on the second try. I am currently using X2GO 4.0.5.0-0x2go1+git20160126.1112+jessie.main.1, Debian GNU/Linux 8, libssh4-0.6.3-4+deb8u1, libc6-2.19-18+deb8u1. Also, I can replicate this issue on Debian 8 - v4.0.3.1-4 and Windows 7 - v4.0.5.0. Any help here would be greatly appreciated. Thanks, Nimesh