Isn't this what your problem is?

   https://askubuntu.com/questions/190194/how-can-i-view-an-x-window-from-a-remote-system-on-their-local-system

Best Regards.

Still no joy! I tried the following incantation in my .bashrc file under /home/marc -

export DISPLAY=local:0.0

and was unable to bring up any desktop manager (I tried all 4 that were offered at the login prompt) Just keeps rejecting my login credentials and cycling back to the login prompt.

Marc...