can't connect to ubuntu using vnc

Hi,

Is the target machine logged in?

I believe that VNC won't work after a reboot, until a user has logged in.

Alan.

Did you install & configure xvnc  or tightvnc server?

Here is an applicable article: https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-vnc-on-ubuntu-16-04

Is the target machine logged in?

yes

Did you install & configure xvnc  or tightvnc server?

tightvncserver

Just a plain install of tightvnc server (apt-get install ...)   or was the xstartup script of use userpart of the vnc server adjusted...
Please compare what you configured to the digital ocean article.  As the digital ocean software uses xfce and you use gnome.

I am flawlessy connecting ubuntu 16.04 server from a Windows machine (RDP) by using this settings. I removed vino and installed x11vnc.
Just follow the procedure in the link.

Is the system in graphical mode?
why not ssh to the system with the option which will redirect  X11 tunnel back through the ssh connection and any graphical interface will be sent back through the X11 tunnel to the X-Windowing system.

Hi,

Also, if you have enabled your firewall then you need to allow the incoming connection from the vnc client.

Cheers

Just a plain install of tightvnc server (apt-get install ...)  

just a plain install

Please compare what you configured to the digital ocean article.

went through that article
session connects but throws constant xfc errors
after a reboot, gui console broke; keeps saying a system error occurred then disappears going back to the login screen regardless whether i select gnome, ubuntu, xfce
was able to get to a command line on console session 2 but probably easier to reinstall.  just installed a couple days ago so not a big deal
then i'll try ssh tunnel (been a while since i did that) and the mint article

Is the system in graphical mode?

yes; session was logged in

Also, if you have enabled your firewall...

firewall disabled

What workstation are you using?, look at installin gift available an X-window app, for Windows xming is a nice tool.
Then use an ssn client with X11 forwarding enabled to localhost:a.b where a.b corresponds to xming,X in the system tray.

When you run an X(graphical) app inthe ssh session, the window will ve sent through the X11 ssh tunnel,,

have you tried with x11vnc, as detailed in my post?

As simple and beautiful was my experience with Ubuntu and x11vnc, but you didn't try.

went a different route