problems with remote gnome sessions

We have recently started having problems with gnome sessions that myself and my colleagues remotely connect to via vnc through ssh tunnel. A brief description is:

1. Start the vnc server
2. Upon connecting to the vnc server through ssh tunnel, the screen is black for ~1 minute.
3. After ~1 minute of black screen, another screen pops up that says "Oh no! Something has gone wrong" and the only option is to click a log out button.