I appreciate the very helpful links, however this has still not helped with the issue.
I have:
-opened port 4000 (security group)
-installed the desktop enviros
-installed nx by copying over the folder and using dpkg as described here: https://www.nomachine.com/DT09K00056&documentName=
-followed these instructions kindly provided by you: https://www.nomachine.com/AR10K00710
at this point I did get a few errors which I am not sure are critical :
Could not init font path element /usr/share/fonts/X11/100dpi/:unscaled, removing from list!
Could not init font path element /usr/share/fonts/X11/75dpi/:unscaled, removing from list!
Could not init font path element /usr/share/fonts/X11/100dpi, removing from list!
Could not init font path element /usr/share/fonts/X11/75dpi, removing from list!
at the nx client, configured to password auth, NX, port 4000, I still get :
Could not connect to the server.
Error is 5: Input/output error
As before this seems strange because it does not ‘try’, the error comes immediately: it does not seemingly take the time to get to the network at all. Possibly I am wrong but this seems to be how it is.
Also I can verify port 4000 is open:
telnet <ip_address> 4000
I have also verified that the service is started on the server, and I have rebooted the server and re run the commands in the article above, just to be sure, still same issue.
If you have any other suggestions, I would greatly appreciate it.