I just installed mailgraph on a Linux Ubuntu 10.04 box monitoring Postifix. Everything seems to be working fine, but the graphs are not always updating. When I refresh the web page or close the browser and come back later, the graph updates and moves to the left, showing new time, the the data line is not drawn. Sometimes it does not update for several hours. I had started, stopped and restarted mailgraph-init and that doesn't seem to make a difference.

Any ideas?