After an upgrade of Qlik Sense, the following errors may be observed.
Accessing the Data Load Editor to review data connections fails with:
Unknown Error
![unknown error.png unknown error.png](https://community.qlik.com/t5/image/serverpage/image-id/170980i160507C6011E44AF/image-size/large?v=v2&px=999)
On the Hub, Creating a new app fails with:
An error occurred.
The app could not be created. Please try again.
![the app could not be created please try again.png the app could not be created please try again.png](https://community.qlik.com/t5/image/serverpage/image-id/170981i145FDABEE75B6B1D/image-size/large?v=v2&px=999)
The Qlik Sense logs (How To Collect Log Files From Qlik Sense Enterprise on Windows) report:
API call to Engine service was not successful: Failed to get app 'StaticByteSize'
Error in EntityChanged event handler Exception of type 'System.Exception' was thrown
Failed setting secure crypto protocols with error code
Resolution
A combination of these errors is typically caused by wrongly configured or mismatched TLS protocols or ciphers or IPv6 settings still present in the Qlik Sense settings file which should have been overwritten during an upgrade.
Any configuration steps in the below solutions must be performed on all nodes.
TLS and ciphers
Verify that the best practices for TLS and SSL support in Qlik Sense are followed and that the same set of TLS versions and cipher suites are used consistently across all components of the environment, especially in a multi-node setup.
For reference:
IPv6 in the settings.ini
Review the Qlik Sense Engine Settings.ini file (C:\ProgramData\Qlik\Sense\Engine\Settings.ini) and remove the line: EnableIPv6Support=0
Additional "Unknown Error" solutions
Follow the instructions in Data connections in Qlik Sense not visible in Data Load Editor or ErrorCode 11041 / 11043 and An error occurred / Failed to load connection error message in Qlik Sense.
Additional "The app could not be created" solutions
See The app could not be created. Please try again - Qlik Sense.
Environment
- Qlik Sense Enterprise on Windows