[6.2.2] cannot connect elastic search secured cluster

[TimV (Tim Vernum)]

From

Setting Up User Authentication | X-Pack for the Elastic Stack [6.2] | Elastic

logstash_system
The user Logstash uses when storing monitoring information in Elasticsearch.

The logstash_system user is used internally within Logstash when monitoring is enabled for Logstash.

You want to look at Configuring Security in Logstash | Logstash Reference [6.2] | Elastic for setting up your own logstash user.