Causes behind Communication Error


We are using vaadin in an embedded mode,(in an iframe of a Page). We have various pages that work in same configuration. We keep on getting Communication error(The big Red box) very randomly, not in all use cases.
Following is the Vaadin Configuration we are using

Version -

Addon -

Heartbeat Interval -
60 sec

closeIdleSession -

Session expired -
2 min

With this configuration, we dont get any kind of communication errors on dev environment. The live users always complain that they get Communication error.

Can you please give some pointers, what are the possibilities where we can get
Communication error
I would really appreciate if you can help me in with this.


Is it any way related to this ticket

BTW, Browser used is IE


You should be aware that Heartbeats isn’t going through websockets (last I checked). This means that an idle websocket will time out eventually unless configured otherwise. (see Why are you using Refresher when push is integrated into Vaadin now?

Hello Erik,

Thanks for your reply, currently we are using Vaadin 7.0.x as part of the application, in a matter of month, 7.1 will be part of our application. And BTW, we are using Poll as PUSH is not supported by our application(IE8/IE9 doesnt support websockets and fallback option httpstreaming is not supported when gzip compression is enabled).

Are there any pointers on what requests to look at? As mentioned in the ticket(8891, though issue is closed), even I am suspecting that some requests are getting lost, but don’t know which one it is. Please let me know if there is a way in troubleshooting this.

The communication error notification should contain a details message that might give a hint on what’s wrong, so you might want to ask for more information from your users. Basically it occurs when the server (or something else, such as a proxy) returns something unexpected, or when the connection to the server fails altogether.

Hello Johannes,

Thank you very much for your inputs, I will checkout with our users for more info regarding the same and will try to troubleshoot this.

Once again, Thank you very much


Hello Johannes,

Attached is the screenshot we have received from the user, can you please give some pointers?
BTW, the user was trying to sort on the table before receiving communication error.