White screen when tried to access a Linux Ubuntu machine from Windows 10

[cfantonio]

Hi,

I’m trying to connect to a headless Ubuntu 18.10 machine using Windows 10 but all I get is a white screen, first time worked perfectly asking if I wanted to create a new display but afterwards I was getting a black screen then trying to fix it after reading several forum posts then now I get just a white screen. Log is attached.

Regards,

Attachments:

1. NoMachine-log.tar-1.gz

[Mth]

Hello.

While there is no indication in the logs why there was problem with the session at first,
the white screen is most likely caused by the Login Window screen on Wayland:

2019-08-30 14:43:41 832.519  1068 NXSERVER checkLocalSession: found X server process: [Xwayland        /usr/bin/Xwayland :1024 -rootless -terminate -accessx -core -listen 4 -listen 5 -displayfd 6]

Currently NoMachine does not work well with Wayland when using proprietary drivers,
or in virtual machines.

In the logs we noticed a standard Xorg server, which should work, but there is no connection attempt.

Please check if disabling Wayland on login window help in this case. Standard
procedure on Ubuntu is to edit /etc/gdm3/custom.conf file and uncomment or add line:

[daemon]
WaylandEnable=false

Please let us know if there are any more problems.

/Mth

[cfantonio]

I disable Wayland and I got a black screen instead of white, but then I restarted gdm and nxserver and I was able to create a virtual screen, many thanks for the help.

Just a quick question is that I’m having trouble to access root directory, it doesn’t show the authentication screen when running virtual screen on headless server.

Regards,

[Mth]

Hello.

Glad to know you can now connect.

Can you explain what you mean when you write “it doesn’t show the authentication screen”? Are you talking about the Login Window screen, or administrator authorization when trying to access the directory? What exactly are you doing?

/Mth

[jjgalvez]

I am having a similar issue with the latest gnome release, using opensource ati drivers. if the computer screen powers off or goes blank nomachine is unable wake up the display and I see only a white screen on the remote side. This only happens with Wayland, If I disable Wayland the display wakes up as expected. Also this only became an issue with the most recent release of gnome 3.34, it was not an issue with gnome 3.32.  I would prefer to use Wayland so I hope this can be fixed in a future release. Happy to include any logs which may be helpful or do further testing

[graywolf]

jjgalvez, would you provide: your Linux OS distribution, the kernel version, the video card model?

Have you got access to the machine on the server side? What do you see if you try to wake up the screen providing some keyboard/mouse input?

[jjgalvez]

Thank you for getting back to me so quickly.

distro: Arch
kernel: 5.3.1
video card: Radeon R7 240 (MSI)
other info: using opensource drivers, DE Gnome 3.34

I have access to the server, when screen is locked and blank, when I try to connect with NoMachine I see a white screen on the client. Nothing happens on the server the screens remains blank. I can wake the server with its keyboard or mouse and the screen opens to the lock screen, which then comes up in the client as well. At this point I can interact with the server again from the client.

[graywolf]

I think I’m able to reproduce on a similar setup. Going to open a Trouble Report.

Meanwhile, would you try this workaround:

1. Edit DisplayServerExtraOptions in /usr/NX/etc/node.cfg in this way:
   DisplayServerExtraOptions "-wlmode compositor"
2. Restart NoMachine: /etc/NX/nxserver --restart
3. Try to connect to view the desktop. If it fails, edit PAM configuration as described here.

[jjgalvez]

Thank you! Editing the DisplayServerExtraOptions and the PAM config in from su to system-login fixed the issue. You are awesome, Wayland is now working again.

[jjgalvez]

BTW this may be something that should be added to the knowledge base.

Again Thank you so much

[graywolf]

You’re welcome. I’ll open a Trouble Report to track this issue.

[Britgirl]

Here is the Trouble Report’s link: https://www.nomachine.com/TR10Q09420

It also includes the known workaround. Please use the ‘notify me’ checkbox to receive notification of when a patch has been officially released.

[Author]

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