Winlogbeat kafka-output seems to be broken

I installed winlogbeat 5.2.2 on a windows Server 2012R2 machine.
winlogbeat sends to the kafka-node, the node creates a topic, but the topic remains empty.
Packages are ariving. I checked via tcpdump . Has someone managed to get the kafka-output plugin for Winlogbeat to work ?

All Beats share the same Kafka output code so this shouldn't be a Winlogbeat specific issue. Others are using this output with success.

What do the logs show on the Winlogbeat side? What configuration are you using?