Removing the instances on CLI works fine. Thanks for this hint.
But another attempt to install the Nethsecurity-Controller app fails again whereas I could install 7 other apps without any problem.
The error message is now:
Assertion failed
File “/var/lib/nethserver/cluster/actions/add-module/50update”, line 230, in
agent.assert_exp(create_module_result[‘exit_code’] == 0) # Ensure create-module is successful
Create-module? Any idea?