Random "Communication problem" and application freeze


We face some random “Communication problem” (see attachement) and application freeze (page became sort of modal white and nothing works anymore) on our server. It seems we are not the only one with this kind of issue, which led to drop Vaadin in some cases:

In our case, the server configuration is quite simple: Apache 2 with ssl and AJP connector to Tomcat 7. We tried with keep-alive OFF. Vaadin version is 7.1.10.

It’s difficult to give more information because it really happens randomly. The only thing is that it’s probably after some idle period (too short for a timeout), and maybe if another application is used and then come back to the Vaadin application.

Any idea / direction to look at to fix this?


I have the same issue. Found as thread that said it was Tomcat 7.024 (ish) and below.
So i upgraded system and still the issue.
Seems to be when the user does nothing for a few minutes, like you say.
Probably going to try to use manual Push instead of automatic.