Google have deprecated their realtime API per January 2019 (see https://developers.google.com/google-apps/realtime/overview) but it's servers are already failing to connect in some cases. The message "No real time collaboration" in the draw.io window means that the file you are viewing was created as a result of such a failure and has real time collaboration disabled to avoid further errors.


We have a replacement system in the work that will be rolled out later this year or early next year.