Hi, we have a full application that works good, but the connected users, receive continuosly and in randow way the message SERVER CONNECTION LOST as a vaadin message, but for US it does not generate any log or sympton what is happening.
In some cases de SERVER CONNECTION LOST, freeze the user session.
Our scenario happens on a very robust internet connection, we already evaluate the network and it is fine… I assume is something that we are missing or not using well on our architecture.
We are working with: vaadin 8, apache tomcat, spring content hibernate on windows server 2016
Can anyone help us ?

We get some user sessions hang after certain file downloads (downloaded via a standard Servlet more than using the File Downloader object). Since we have “preserve on refresh” set to the webapp, if they refresh their browser it comes back.

But we also suffer Tomcat freezes (TC 9) after some user activity that then requires we restart Tomcat as most user activity seems to get hung up. We’ve not been able to uncover the reason. The server doesn’t appear overly busy, DB connections seem to work, etc. It’s a lot more tricky with websockets going as we cannot really see most of the client-server interactions.

We are experiencing the exact same issues.Getting SERVER CONNECTION LOST at trivial tasks and after that is freezing the user session. We have taught by extending the heartbeat will solve the problem, but it did not.
Can you give some insight on this ?
We are using vaadin8.4.2.

Hi We are facing the same issue , Does anyone got solution for it?
We have tried with annotation @PreserveOnRefresh to the UI class and also tried UI.setPollingInterval(5000);

Can anyone give solution for this?