"Invalid Session" dialog from Wisej after beeing away


From time to time we got an “Invalid Session” dialog from our Wisej WebApplication, if we left for several minutes the browser tab.

It took some time, but I think now we found the reason for that.

In our application we set the SessionTimeout in default.json to 8h.

IIS-Settings are set to default. So, SessionTimeout and ApplicationPool timeout are set to 20min.

I was looking for some KeepAliveSignal/HeartbeatSignal in defalut.json documentation, but without success.

Looking at the Wisej-Sources I finally found something. It is called keepAliveInterval and you can set it also in default.json.

But per default it is calculated in dependence of the SessionTimeout, which is set in default.json. So, in our case we have a SessionTimeout of 8h, which means that keepAliveInterval is set by Wisej to 2h. As a result of this, if no one interacts with the application for 20min, the application pool was cleaned up and we got the “Invalid Session” message box.

Possible solutions are now:

  1. Setting the SessionTimeout in default.json to a value that the calculated keepAliveInterval is smaller than the ApplicationPool timeout.
  2. Set the undocumented “keepAliveInterval” in defalut.json to a value smaller the ApplicationPool timeout.
  3. Set the ApplicationPool timeout to 0, so it will never be kicked.


We could only reproduce this behavior, when setting “enableWebSocket”: false in default.json.

Could it be, because of the duplex WebSocket connection the KeepAlive is send on a different way?


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Hi Jens,

IIS settings are not handled by Wisej and setting a higher session timeout in Wisej than in IIS is a wrong configuration.
So I think it´s better to fix that configuration instead.

Best regards

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