Qlik Sense Error - Connection Lost

[neerajthakur]

Hi,

We are using Qlik Sense Enterprise Nov 2025 and we are getting Error Code : 16, Connection lost error, frequently on our client system in like 2-3 minutes or even early.

What could be the issue, I have read many articles but none of them seems to work, was using Qlik Feb 2023, there also we had same problem and wasn't able to resolve in 2024 and just accepted it to resolve on its own.

[Eduardo_Monteiro]

Hi @neerajthakur 

Try the following:

• Open browser DevTools → Network → WS filter, reproduce the drop, and note the time-to-disconnect (consistent ~120s/180s = idle timeout) and the close code (1006 = something in the network path killed it).
• Test a direct connection to the server node (bypass load balancer / reverse proxy / VPN), e.g. https://<node-hostname>/hub — add the hostname to the virtual proxy Host allow list first. If direct is stable, the middle layer is the culprit.

Also, check logs at the drop timestamp: Proxy\Trace\*Audit* and Engine\Trace\*System* in C:\ProgramData\Qlik\Sense\Log.

I hope that helps.

BR,