Need Ubuntu Linux person to install a desktop view on virtual machine google cloud compute instance

I have a new virtual machine with ubuntu 16.04 - I have followed this guide to install a VNC desktop - [login to view URL] I installed gnome and can access via vncviewer but when it loads, the attached error message happens. I need someone to quickly fix that error so I can login to the desktop. Also, I need to confirm that the instance is setup securely as this will be running an IOS app. Please PM me for the login credentials, need this asap today thanks. I also need to point a domain name to this server so we can access this instead of via the IP I just need to know wick nameservers to use, or which dns record to change.