Internal Server Error when opening Hub

Benjamin_C — Wed, 26 May 2021 13:29:33 GMT

In QlikSense, Hub login page is accessible but issue happens after username and password is provided with the error message "Internal Server Error" displayed. Qlik Management Console (QMC) has no issues.

Environment:

This can have multiple root causes.

The Load Balancing URI

When looking into browser developer tool F12 it registers: (Save network web traffic (HAR/XML file) and console logs from the browser's developer tools)

"500 (Cannot get engine services from the load balancing module for the following app: __hub)"

Opening an app directly also says there is no engine available. Does not matter which user is login nor which app is opened.

Load balancing URI in virtual proxy used but not set up correctly

To resolve:

Remove/modify settings under QMC -> Virtual Proxies -> Edit virtual proxy -> Central -> Integration -> Load balancing module base URI

Settings depend on the 3rd party load balancer used.

Port 9028 not listening, wrong parameters configured

Verify the [hub.parameters].

Stop the Qlik Sense Dispatcher Service
Locate C:\Program Files\Qlik\Sense\ServiceDispatcher\services.conf
Take a backup of the service.conf file
Open the file and locate [hub.parameters]
Locate and remove the following to parameters:
- --high-dpi-support=1
- --force-device-scale-factor=1
Start the Service Dispatcher services once the changes are done.

Cause:

Port 9028 was not listening because of the below two parameters present in C:\Program Files\Qlik\Sense\ServiceDispatcher\services.conf and under [hub.parameters] and save the confg file.

Port 4900 and 4747 not available

Reviewing the Proxy's Trace System_Proxy logs indicates an issue with connectivity on port 4900.
Reviewing the Proxy's Trace Audit_Proxy logs indicates an issue with WebSocket connectivity on port 4747.

These ports are used by Qlik Sense Engine and Blocking services. See Sense used Ports.

The result of the following commands indicate PIDs that are not of Qlik Sense services origin:

netstat -bano | findstr :4900
netstat -bano | findstr :4747

Cause

Third-party applications such as HFSQL / HyperFile use port 4900 which may cause conflicts.
Note: Only port 4900 is documented to be used by HFSQL publicly.

article Internal Server Error when opening Hub in Official Support Articles