Monitoring User for Logstash

[TimV (Tim Vernum)]

@toni

curl -XPUT _xpack/security/user/logstash_system/_enable'
{"error":{"root_cause":[{"type":"validation_exception","reason":"Validation Failed: 1: only > existing users can be enabled;"}],"type":"validation_exception","reason":"Validation > Failed: 1: only existing users can be enabled;"},"status":400}

Did you copy this exactly from your cluster?
As best I can tell that error message has not existed in any recent version of X-Pack/Elasticsearch (I checked from 6.0.0 to 6.2.0)

What do you get for:

GET /_xpack/security/user/

and

GET /_xpack/