Logstash ERROR: Unable to retrieve license information from license server {:message=>"Unrecognized SSL message, plaintext connection?"}

Hi,

I have a cluster consisting of 3 nodes and an installation of kibana and logstash, all to version 6.8.1.

I followed the procedure to configure SSL, TLS and HTTPS certificates:

The Elasticsearch nodes are working, Kibana is working, Logstash has this error at startup:

[ERROR][logstash.licensechecker.licensereader] Unable to retrieve license information from license server {:message=>"Unrecognized SSL message, plaintext connection?"}
[ERROR][logstash.monitoring.internalpipelinesource] Failed to fetch X-Pack information from Elasticsearch. This is likely due to failure to reach a live Elasticsearch cluster.

Can you help me?

Thanks

Daniele

Do you have xpack.monitoring.elasticsearch.hosts set with https:// prefix and the necessary ssl.certificate_authority files?

It may help to post your logstash.yml config (format with </>)