I also have some additional information from the environment.

ldd nxagent -ac :1
nxagent:
        linux-vdso.so.1 =>  (0x00007fffa63ff000)
        libX11.so.6 => /usr/lib64/libX11.so.6 (0x0000003eb5400000)
        libXcomp.so.3 => /usr/lib64/libXcomp.so.3 (0x00000030d8200000)
        libXcompshad.so.3 => /usr/lib64/libXcompshad.so.3 (0x00000030d7600000)
        libXrender.so.1 => /usr/lib64/libXrender.so.1 (0x0000003eb7400000)
        libXfixes.so.3 => /usr/lib64/libXfixes.so.3 (0x0000003eb8000000)
        libXfont.so.1 => /usr/lib64/libXfont.so.1 (0x00000030d6600000)
        libXcomposite.so.1 => /usr/lib64/libXcomposite.so.1 (0x0000003ebb800000)
        libXinerama.so.1 => /usr/lib64/libXinerama.so.1 (0x0000003eb8800000)
        libXdmcp.so.6 => /usr/lib64/libXdmcp.so.6 (0x0000003ebcc00000)
        libNX_X11.so.6 => /usr/lib64/nx/libNX_X11.so.6 (0x00000030d6e00000)
        libXext.so.6 => /usr/lib64/libXext.so.6 (0x0000003eb6400000)
        libz.so.1 => /lib64/libz.so.1 (0x0000003eb3800000)
        libm.so.6 => /lib64/libm.so.6 (0x0000003eb2c00000)
        libXpm.so.4 => /usr/lib64/libXpm.so.4 (0x0000003ec0000000)
        libxml2.so.2 => /usr/lib64/libxml2.so.2 (0x00000030d7200000)
        libpixman-1.so.0 => /usr/lib64/libpixman-1.so.0 (0x0000003ebb000000)
        libpng12.so.0 => /usr/lib64/libpng12.so.0 (0x0000003eb6800000)
        libjpeg.so.62 => /usr/lib64/libjpeg.so.62 (0x0000003ec1400000)
        libc.so.6 => /lib64/libc.so.6 (0x0000003eb2400000)
        libxcb.so.1 => /usr/lib64/libxcb.so.1 (0x0000003eb5000000)
        libdl.so.2 => /lib64/libdl.so.2 (0x0000003eb3000000)
        libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x0000003ebd400000)
        libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x0000003ebc800000)
        libNX_Xext.so.6 => /usr/lib64/nx/libNX_Xext.so.6 (0x00000030d8a00000)
        libNX_Xtst.so.6 => /usr/lib64/nx/libNX_Xtst.so.6 (0x00000030d8600000)
        libNX_Xrandr.so.2 => /usr/lib64/nx/libNX_Xrandr.so.2 (0x00000030d8e00000)
        libNX_Xdamage.so.1 => /usr/lib64/nx/libNX_Xdamage.so.1 (0x00000030d7a00000)
        libfreetype.so.6 => /usr/lib64/libfreetype.so.6 (0x0000003eb7000000)
        libfontenc.so.1 => /usr/lib64/libfontenc.so.1 (0x00000030d7e00000)
        libpthread.so.0 => /lib64/libpthread.so.0 (0x0000003eb2800000)
        /lib64/ld-linux-x86-64.so.2 (0x0000003eb2000000)
        libXau.so.6 => /usr/lib64/libXau.so.6 (0x0000003eb5c00000)
        libNX_Xrender.so.1 => /usr/lib64/nx/libNX_Xrender.so.1 (0x00000030d6a00000)


readelf -d nxagent
Dynamic section at offset 0x409d10 contains 40 entries:
  Tag        Type                         Name/Value
 0x0000000000000001 (NEEDED)             Shared library: [libX11.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libXcomp.so.3]
 0x0000000000000001 (NEEDED)             Shared library: [libXcompshad.so.3]
 0x0000000000000001 (NEEDED)             Shared library: [libXrender.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libXfixes.so.3]
 0x0000000000000001 (NEEDED)             Shared library: [libXfont.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libXcomposite.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libXinerama.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libXdmcp.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libNX_X11.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libXext.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libz.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libm.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libXpm.so.4]
 0x0000000000000001 (NEEDED)             Shared library: [libxml2.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [libpixman-1.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libpng12.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libjpeg.so.62]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]
 0x000000000000000f (RPATH)              Library rpath: [/usr/lib64/nx/X11]
 0x000000000000001d (RUNPATH)            Library runpath: [/usr/lib64/nx/X11]
 0x000000000000000c (INIT)               0x409298
 0x000000000000000d (FINI)               0x727088
 0x000000006ffffef5 (GNU_HASH)           0x400298
 0x0000000000000005 (STRTAB)             0x403970
 0x0000000000000006 (SYMTAB)             0x400400
 0x000000000000000a (STRSZ)              8398 (bytes)
 0x000000000000000b (SYMENT)             24 (bytes)
 0x0000000000000015 (DEBUG)              0x0
 0x0000000000000003 (PLTGOT)             0xa09fe8
 0x0000000000000002 (PLTRELSZ)           12720 (bytes)
 0x0000000000000014 (PLTREL)             RELA
 0x0000000000000017 (JMPREL)             0x4060e8
 0x0000000000000007 (RELA)               0x405f98
 0x0000000000000008 (RELASZ)             336 (bytes)
 0x0000000000000009 (RELAENT)            24 (bytes)
 0x000000006ffffffe (VERNEED)            0x405eb8
 0x000000006fffffff (VERNEEDNUM)         5
 0x000000006ffffff0 (VERSYM)             0x405a3e
 0x0000000000000000 (NULL)               0x0


gdb nxagent
GNU gdb (GDB) Red Hat Enterprise Linux (7.2-56.el6)
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/bin/nxagent...(no debugging symbols found)...done.
Missing separate debuginfos, use: debuginfo-install nxagent-3.5.99.20-0.0build1.1.git20190425.3309.main.el6.x86_64
(gdb) r -ac :1
Starting program: /usr/bin/nxagent -ac :1
[Thread debugging using libthread_db enabled]

NXAGENT - Version 3.5.99.20

Copyright (c) 2001, 2011 NoMachine (http://www.nomachine.com)
Copyright (c) 2008-2014 Oleksandr Shneyder <o.shneyder@phoca-gmbh.de>
Copyright (c) 2011-2016 Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
Copyright (c) 2014-2016 Ulrich Sibiller <uli42@gmx.de>
Copyright (c) 2014-2016 Mihai Moldovan <ionic@ionic.de>
Copyright (c) 2015-2016 Qindel Group (http://www.qindel.com)
See https://github.com/ArcticaProject/nx-libs for more information.

Info: Agent running with pid '31252'.
Session: Starting session at 'Fri Sep 20 15:39:37 2019'.
Info: Using alpha channel in render extension.
nxagent: xcb_io.c:520: _XAllocID: Assertion `ret != inval_id' failed.

Program received signal SIGABRT, Aborted.
0x0000003eb24324f5 in raise () from /lib64/libc.so.6



De: Elder Vicente <eldereng@hotmail.com>
Enviado: sexta-feira, 20 de setembro de 2019 14:54
Para: submit@bugs.x2go.org <submit@bugs.x2go.org>
Assunto: x2gostartagent: X2Go Agent terminated unexpectedly
 
Package: x2goserver
Version: 4.1.0.3-0.0
 

Hello,
I have a server (Centos 6) with Gnome, SSH and X2goServer.
The accesses by SSH is ok, but X2goClient (4.1.2.0 - Windows) do not work.
On server-side, I have this message: "/usr/bin/x2gostartagent: Failed to start X2Go Agent session with ID elder2-50-1568998198_stDGNOME_dp32. X2Go Agent terminated unexpectedly. Aborting session startup."
Can you help me?




Packages installed:
x2goserver-x2goagent-4.1.0.3-0.0x2go1.1.git20181129.1708.main.el6.x86_64
perl-X2Go-Server-DB-4.1.0.3-0.0x2go1.1.git20181129.1708.main.el6.x86_64
x2goserver-extensions-4.1.0.3-0.0x2go1.1.git20181129.1708.main.el6.x86_64
perl-X2Go-Log-4.1.0.3-0.0x2go1.1.git20181129.1708.main.el6.x86_64
x2goserver-common-4.1.0.3-0.0x2go1.1.git20181129.1708.main.el6.x86_64
x2goserver-xsession-4.1.0.3-0.0x2go1.1.git20181129.1708.main.el6.x86_64
perl-X2Go-Server-4.1.0.3-0.0x2go1.1.git20181129.1708.main.el6.x86_64
x2goserver-4.1.0.3-0.0x2go1.1.git20181129.1708.main.el6.x86_64


Log on /var/log/messages:
Sep 20 13:49:57 saserver /usr/bin/x2gostartagent: x2gostartagent called with options: 800x600 adsl 16m-jpeg-9 unix-kde-depth_32 us auto 1 D GNOME both
Sep 20 13:49:58 saserver /usr/bin/x2gosessionlimit[7133]: x2gosessionlimit has been called
Sep 20 13:49:58 saserver x2golistsessions: x2golistsessions has been called with options: --all-servers
Sep 20 13:50:00 saserver /usr/bin/x2gofeature: x2gofeature called with options: X2GO_RUN_EXTENSIONS
Sep 20 13:50:00 saserver /usr/share/x2go/x2gofeature.d/x2goserver-extensions.features: x2goserver-extensions.features called with options: X2GO_RUN_EXTENSIONS
Sep 20 13:50:00 saserver /usr/bin/x2goserver-run-extensions: x2goserver-run-extensions called with options: elder2-50-1568998198_stDGNOME_dp32 pre-start
Sep 20 13:50:00 saserver /usr/bin/x2gostartagent: creating new session: elder2-50-1568998198_stDGNOME_dp32 59781d72342a249f29eaa296a45a2326 7256 200.131.62.254 45498 45499 45500 -1 -1
Sep 20 13:50:01 saserver /usr/bin/x2gostartagent: Failed to start X2Go Agent session with ID elder2-50-1568998198_stDGNOME_dp32. X2Go Agent terminated unexpectedly. Aborting session startup.
Sep 20 13:50:01 saserver /usr/bin/x2gofeature: x2gofeature called with options: X2GO_RUN_EXTENSIONS
Sep 20 13:50:01 saserver /usr/share/x2go/x2gofeature.d/x2goserver-extensions.features: x2goserver-extensions.features called with options: X2GO_RUN_EXTENSIONS
Sep 20 13:50:01 saserver /usr/bin/x2goserver-run-extensions: x2goserver-run-extensions called with options: elder2-50-1568998198_stDGNOME_dp32 fail-start