[o.e.c.InternalClusterInfoService] Failed to execute IndicesStatsAction for ClusterInfoUpdateJob because it is unable to authenticate the user. I have a custom authentication extension in x-pack and it is failing on that. I had the same sort of setup in my 2.3.3 cluster (with a custom auth), and everything seems to be running smoothly
I have tried enabling file and native realms and changed the orders in my elasticsearch.yml file but it is still hitting my custom auth and failing.