Weird kibana exception after authentication

[pkaramol (Pantelis Karamolegkos)]

I am able to access the initial page of my kibana instance.

After however providing username and password, I see this in my web browser page

{"statusCode":500,"error":"Internal Server Error","message":"illegal_state_exception"}

{"type":"error","@timestamp":"2021-11-03T16:03:38+00:00","tags":[],"pid":8,"level":"error",
"error":{"message":"Internal Server Error","name":"Error","stack":"Error: Internal Server Error
    at HapiResponseAdapter.toError (/usr/share/kibana/src/core/server/http/router/response_adapter.js:121:19)
    at HapiResponseAdapter.toHapiResponse (/usr/share/kibana/src/core/server/http/router/response_adapter.js:75:19)
    at HapiResponseAdapter.handle (/usr/share/kibana/src/core/server/http/router/response_adapter.js:70:17)
    at interceptRequest (/usr/share/kibana/src/core/server/http/lifecycle/on_post_auth.js:58:36)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
    at exports.Manager.execute (/usr/share/kibana/node_modules/@hapi/hapi/lib/toolkit.js:60:28)
    at Request._invoke (/usr/share/kibana/node_modules/@hapi/hapi/lib/request.js:397:30)
    at Request._lifecycle (/usr/share/kibana/node_modules/@hapi/hapi/lib/request.js:370:32)
    at Request._execute (/usr/share/kibana/node_modules/@hapi/hapi/lib/request.js:279:9)"},
"url":"http://my-kibana.mysubdomain.domain.com/","message":"Internal Server Error"}

Error in elasticsearch logs

"stacktrace": ["java.lang.IllegalStateException: Duplicate key feature_graph.read (attempted merging values ApplicationPrivilegeDescriptor{[kibana-.kibana],[feature_graph.read],[saved_object:7.6.2:graph-workspace/find,ui:7.6.2:catalogue/graph,login:,version:7.6.2,saved_object:7.6.2:graph-workspace/bulk_get,saved_object:7.6.2:config/find,saved_object:7.6.2:index-pattern/get,saved_object:7.6.2:url/bulk_get,saved_object:7.6.2:url/find,app:7.6.2:graph,saved_object:7.6.2:index-pattern/bulk_get,saved_object:7.6.2:url/get,app:7.6.2:kibana,saved_object:7.6.2:config/get,saved_object:7.6.2:index-pattern/find,ui:7.6.2:navLinks/graph,saved_object:7.6.2:graph-workspace/get,saved_object:7.6.2:config/bulk_get]} and ApplicationPrivilegeDescriptor{[kibana-.kibana],[feature_graph.read],[saved_object:7.12.1:telemetry/find,app:7.12.1:graph,ui:7.12.1:navLinks/kibana,saved_object:7.12.1:url/close_point_in_time,saved_object:7.12.1:telemetry/open_point_in_time,saved_object:7.12.1:index-pattern/open_point_in_time,ui:7.12.1:graph/show,saved_object:7.12.1:url/find,saved_object:7.12.1:telemetry/close_point_in_time,saved_object:7.12.1:graph-workspace/close_point_in_time,saved_object:7.12.1:graph-workspace/bulk_get,saved_object:7.12.1:telemetry/bulk_get,saved_object:7.12.1:telemetry/get,app:7.12.1:kibana,saved_object:7.12.1:url/get,ui:7.12.1:navLinks/graph,saved_object:7.12.1:index-pattern/bulk_get,login:,saved_object:7.12.1:config/close_point_in_time,version:7.12.1,saved_object:7.12.1:index-pattern/get,saved_object:7.12.1:index-pattern/close_point_in_time,saved_object:7.12.1:index-pattern/find,saved_object:7.12.1:graph-workspace/get,saved_object:7.12.1:graph-workspace/open_point_in_time,saved_object:7.12.1:config/get,saved_object:7.12.1:config/find,saved_object:7.12.1:url/open_point_in_time,saved_object:7.12.1:graph-workspace/find,saved_object:7.12.1:config/open_point_in_time,ui:7.12.1:catalogue/graph,saved_object:7.12.1:url/bulk_get,saved_object:7.12.1:config/bulk_get]})",

Elasticsearch (7.12.1) and Kibana (7.12.1) are deployed using ECK but not sure if this is related.

[zx8086]

Duplicate error might mean you have the same parameter or setting configured twice. Maybe adding a field that already existed in the configuration files you changed.