Cannot reconnect after upgrading Ubuntu 22.04 to 24.04

[Jugdish]

NoMachine Host: 8.11.3 (Ubuntu)
NoMachine Player: 8.11.3 (Windows 10)

I’ve been running 8.11.3 without issue for months. I recently upgraded my host machine from Ubuntu 22.04 to 24.04 and ever since then my NoMachine Host has changed behavior. I am now only able to connect one time. After closing that session and attempting to reconnect, I am unable to — Player reports “Connection timed out” errors. I have to restart (“sudo /etc/NX/nxserver –restart”) which will again allow me to connect only one time.

The intended behavior that I want is to have a virtual desktop session initialized on first connect, which then persists on disconnect and is resumed on any subsequent reconnect. Again, it was behaving without issue before I upgraded Ubuntu.

/usr/NX/etc/nxserver.cfg:

ConfigFileVersion 4.0
SessionLogLevel 7
SystemLogFile /var/log/NX/nxserver.log
ConnectionsLimit 0
ConnectionsUserLimit 0
VirtualDesktopsLimit 0
VirtualDesktopsUserLimit 0
EnablePersistentSession all
EnableClipboard both
EnableUserDB 0
EnablePasswordDB 0
ConnectPolicy autocreate=1,autoconnect=1,automigrate=1,desktop=0,dialog=0,xsessions=0,udp=1
ClientConnectionMethods NX,SSH
SSHAuthorizedKeys authorized_keys
AvailableSessionTypes unix-remote,unix-console,unix-default,unix-application,physical-desktop,shadow,unix-xsession-default,unix-gnome,unix-xdm
DisconnectedSessionExpiry 0
CreateDisplay 1
DisplayGeometry 1920×1080
AcceptedAuthenticationMethods NX-private-key
Section Server
Name Connection to localhost
Host 127.0.0.1
Protocol NX
Port 4000
EndSection
WebReferrer “”
WebRedirect “”

/usr/NX/etc/node.cfg:

ConfigFileVersion 4.0
SessionLogLevel 7
DefaultDesktopCommand “dbus-launch –exit-with-session startxfce4”
AvailableSessionTypes unix-remote,unix-console,unix-default,unix-application,physical-desktop,shadow,unix-xsession-default,unix-gnome,unix-xdm
EnableSmartcardSharing 1
AudioInterface pulseaudio
CommandStartPulseAudio “/usr/bin/pulseaudio –high-priority=no”
CommandStartPipeWire “/usr/bin/pipewire -c”
EnableCUPSSupport 1
CUPSBinPath /usr/bin
CUPSSbinPath /usr/sbin
CUPSBackendPath /usr/lib/cups/backend
EnableSMBFSSupport 0
CommandStartGnome “dbus-launch –exit-with-session gnome-session –session=ubuntu”
CommandFuser /usr/bin/fuser
CommandLsof /usr/bin/lsof
CommandXdpyInfo /usr/bin/xdpyinfo
CommandXmodmap /usr/bin/xmodmap
CommandXkbComp /usr/bin/xkbcomp
DefaultXSession “/etc/X11/Xsession default”
ClientConnectionMethods NX,SSH
DisplayServerThreads auto
DisplayEncoderThreads auto
EnableDirectXSupport 0
DefaultConsole xterm
EnableDbusLaunch 1
EnableScreenBlankingEffect 1
EnableAudio 1

Attached is a copy of nxserver.log during the period of time in which I was attempting to re-connect after having closed the client window. There seems to the following repeated over and over:

3838430 3838430 2024-06-15 14:24:51 903.428 NXSERVER Handle state: limits reached.
3838430 3838430 2024-06-15 14:24:51 903.606 NXSERVER Handle connections limit reached.
3838430 3838430 2024-06-15 14:24:51 903.639 NXSERVER Searching the oldest connected session.
3838430 3838430 2024-06-15 14:24:51 903.940 NXSERVER Cannot find oldest session.
3838430 3838430 2024-06-15 14:24:51 903.971 NXSERVER The oldest connection closed. Continue session start.
3838430 3838430 2024-06-15 14:24:52 005.707 NXSERVER Handle state: create session in dabatase.
3838430 3838430 2024-06-15 14:24:52 005.746 NXSERVER Handle limits.
3838430 3838430 2024-06-15 14:24:52 005.784 NXSERVER This session in not forwarded.
3838430 3838430 2024-06-15 14:24:52 006.262 NXSERVER NXLimits: Checking limits node ‘699ac2fa-bba8-4497-b90f-ecd23c5f56ae’ user ‘jugdish’ type ‘physicalAttachDesktop’.
3838430 3838430 2024-06-15 14:24:52 006.448 NXSERVER NXLimits: Connections 1/1 user 1/0 node 1/0.
3838430 3838430 2024-06-15 14:24:52 006.529 NXSERVER Session start state machine: Handling state: handleLimitsReached.
3838430 3838430 2024-06-15 14:24:52 006.565 NXSERVER Handle state: limits reached.

Why is this happening? What limit is being reached, why can’t it find the oldest session, and why is it checking ‘physicalAttachDesktop’ if I only want virtual desktop sessions?

[Britgirl]

The free version of NoMachine supports one incoming connection to the system. Have you always been using the free version? Maybe you installed the free version thinking you were installing one of the other products?

[Jugdish]

I am not trying to connect more than once at the same time, I am simply trying to resume a single session later, and I’m unable to. To clarify, these are the steps:

1. Start nxserver
2. Connect via a client. A new virtual desktop is created.
3. Close that client window. The virtual desktop remains running on the server, and there are no clients connected to it.
4. Later, try to connect via a client again. I am using the exact same connection file and credentials. But the server is unable to connect me with the already created virtual desktop session. The logs say connection limit reached and unable to locate last session.

[Britgirl]

We need to see NoMachine server-side logs. These must be taken from the machine you are connecting to.

Instructions are here:
https://kb.nomachine.com/DT07S00243#2

You can send them to forum[at]nomachine[dot]com or attach them here.

[Author]

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