Errors while using Vaadin application - How to find them?


I have a problem with our Vaadin application in production environment. I implemented something like a Gantt chart using a Canvas to draw all necessary things on client side. The chart is also interactive, that means, you can drag’n’drop things and so on.
But sometimes a problems occurs. During using the application/chart the canvas gets totally white. It only occurs in production environment randomly. It looks like, there is a problem within Vaadin communication between server and client or something like that.
What would you suggest to find the problem? There is no exception on client side (tested with debug mode), there is no error in the “normal” log files. I also simulated bad network connection with a lot of package loss, small bandwidth and so on. But no problem at all (except slownes).
What else can I do? Are there more logging possibilities available? Should I re-configure something in Vaadin communication, …
Every hint is welcome. I really do not know, what else I can do or what could be the problem…
I am using Vaadin 8.

Thanks a lot