Failed to open display ‘:0’ NoMachine 7.8.2, Ubuntu 18.04 Desktop

[GarryHeck]

Hi all,  could you help me, please

After the update, I can’t connect to the NoMachine server. Please advise where to look for the problem. On the client it says “no desktops available”. Perhaps the problem is related to gdm3, but I do not have enough competencies to solve the problem.

log nxerror

No protocol specified
24794 24905 14:28:08 004.682 HostWmRunningHelper: WARNING! Failed to open display ‘:1024’.
No protocol specified
24794 24906 14:28:08 004.989 HostWmRunningHelper: WARNING! Failed to open display ‘:1024’.
/usr/bin/xauth:  file /var/lib/gdm3/.Xauthority does not exist
No protocol specified
24794 24945 14:28:08 150.428 HostWmRunningHelper: WARNING! Failed to open display ‘:0’.
Invalid MIT-MAGIC-COOKIE-1 key24794 24954 14:28:08 180.099 HostWmRunningHelper: WARNING! Failed to open display ‘:0’.

$ env DISPLAY=:0 xhost
access control enabled, only authorized clients can connect
SI:localuser:dkudr

[Britgirl]

This looks similar to: https://forums.nomachine.com/topic/black-screen-no-protocol-specified-warning-failed-to-open-display-0 which was a problem with Wayland. Following the instructions in our article about headless Linux machines https://knowledgebase.nomachine.com/AR03P00973 solved the problem.

[GarryHeck]

How can I cancel a virtual session?

/usr/NX/bin/nxserver.bin --virtualsession --sessionid 64E68BDA

[Britgirl]

You can use --terminate or simply --restart nxserver.

Terminating the Session from Command Line

To terminate a virtual desktop or remote desktop session you can run:
nxserver --terminate SESSIONID or:

nxserver --terminate DISPLAYID

To terminate sessions of a certain user, run instead:
nxserver --terminate USERNAME

Finally, if you want to terminate all sessions, just restart the server:
nxserver --restart

or shutdown if you want to forbid new connections until the server is started again:
nxserver --shutdown

[GarryHeck]

I upgraded to version 7.9.2. The session is connected, but on the client again an error “No available desktops”

● nxserver.service – NoMachine Server daemon
Loaded: loaded (/lib/systemd/system/nxserver.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2022-03-28 13:13:12 MSK; 27min ago
Main PID: 5734 (nxserver.bin)
Tasks: 41 (limit: 4421)
CGroup: /system.slice/nxserver.service
├─5734 /usr/NX/bin/nxserver.bin –daemon
├─5785 /usr/NX/bin/nxd -p <***>
└─8163 /usr/NX/bin/nxserver.bin -c /etc/NX/nxserver –login -H 5

мар 28 13:13:12 dkudr-510-22ISH systemd[1]: Started NoMachine Server daemon.
мар 28 13:13:13 dkudr-510-22ISH nxexec[5853]: pam_unix(nx:session): session opened for user dkudr by (uid=122)
мар 28 13:17:13 dkudr-510-22ISH nxexec[6364]: pam_unix(nx:session): session opened for user dkudr by (uid=122)

I see errors in the logs

3044 3109 13:05:49 803.214 ServerNetworkInfoHandler: WARNING! Obtaining network data failed with result -100.
3044 3044 13:13:12 583.055 HostDescriptorClose: WARNING! Descriptor FD#36 is invalid

3044 3044 2022-03-28 13:13:09 862.627 NXSERVER WARNING! Timeout of 10 seconds reached for terminating of node process with pid 3169.

 

[Britgirl]

Hi, submit those attachments to forum[at]nomachine[dot]com.  Did you follow the instructions that I wrote in my earlier reply from last week?

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