Hello Joe
Welcome to Microsoft Q&A Platform, thanks for posting your query here.
It looks like you are trying to start the X server as a non-root user, which is not allowed by default on Ubuntu. You can try running the following command to allow non-root users to start the X server:
sudo dpkg-reconfigure x11-common
This will bring up a configuration dialog where you can select "Anybody" under "Console users" and then click "OK" to save the changes.
After making this change, you should be able to start the X server as a non-root user by running the startx command again. If you still encounter issues, you can try running the command with the -- :1 option to start the X server on a different display:
startx -- :1
This will start the X server on display :1 instead of the default display :0. You can then connect to the X server using a VNC client or another remote desktop solution.
Hope this helps.