Splunk Integration - no logs visible in Splunk

I think I have configured everything correctly, but there are no logs visible in splunk.
My setup:
HA(hassio) 100.2 and splunk 7.3.2 on docker on ubuntu.
no ssl for the connection, it seems to work, I get no errors in HA.
But there are no logs in splunk (using the HA splunk app)

The htttp event collector is working:
curl -k http://localhost:8088/services/collector/event -H “Authorization: Splunk <<<<>>>>>” -d ‘{“event”: “hello world”}’

So I’m a bit lost - any ideas?

I must confess, I’m a splunk noob - I realized that I have data in splunk, I just have to select the “homeassistant” index.
But even if the data is in there, the home assistant splunk app doesn’t show any data. The correct index is selected, but I guess the search syntax is incorrect. Anybody using splunk out there who can give me some useful queries?