Users experiencing intermittent errors where the App load will be stuck in initializing for two minutes before advancing and the Hub will display the following error:
Connection lost. Make sure that Qlik Sense is running properly. If your session has timed out due to inactivity, refresh to continue working.
When this issue occurs the behavior will be seen by all users and a restart of the Qlik Sense repository services will restore normal operation (though in some deployments temporarily)
A HAR file or review of the developer tools of the Hub will show the Hub attempting to establish a connection to the qrsData WebSocket and then failing with the error message on the Hub and app load resuming once the WebSocket fails.
Additionally, if the Trace > Audit logs for the Proxy service are set to Debug the following error will be seen:
Connection <Connection_ID> has been transferred to a streaming state to send a single error message <client_IP_address> <host>:4239
Port 4239 is the port used by the qrsData WebSocket.
Environment
- Qlik Sense Enterprise on Windows
Cause
This behavior was discovered in environments running the Tenable penetration test against the Qlik Sense servers, although this could be caused by other penetration testing software or other code that meets the conditions to cause the behavior.
The error is caused by a combination of timing and error handling in which a large number of bad requests are made without certificates, such that the connection is closed before Qlik Sense finishes validating the request. In this scenario, Qlik Sense does not handle the error gracefully and requires a restart of the Repository service to recover.
The error condition does not come up under normal operations due to how quickly the validation runs but the rapid requests from penetration test can lead to the error condition described.
Qlik will release a fix in a future patch that will allow Qlik Sense to handle this scenario gracefully.
Workaround:
Unless specifically targeting Qlik Sense (including maintenance where applicable), exclude Qlik Sense from penetration tests.
An alternative is a scheduled restart of the Qlik Sense services following the completion of the penetration test.
Fix Version:
- May 2024 Patch 6
- February 2024 Patch 10
- November 2023 Patch 13
- August 2023 Patch 15
- May 2023 Patch 17
Internal Investigation ID(s):
QB-29033
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