Can't connect to Lish Ajax Console

I can't connect to the Lish Ajax Console form my home machine, I just get a screen with "invalid session, session closed" and a "connect" button which doesn't connect but loops back to invalid session.

However,,,I had some network connection problems recently and couldn't connect via Putty so had to resort to using Glish as a CLI interface which doesn't support copy/paste (which is a pain for a newbie trying to enter long commands), but from work where I'm behind a firewall, I managed to connect to the Lish Ajax console for the first time?!?

Anyone know why I can't connect from home? It would be handy if/when I encounter another network issue

btw OS is Ubuntu 16.04