Kibana 6.2.4: Visualize: unknown error

[asp]

Hi there,

Versions:
Elasticsearch: 6.2.3
Kibana: 6.2.4

very often I get following error in kibana during autorefresh of a complex dashboard:

Visualize: unknown error

 Less Info
OK
Error: unknown error
    at respond (https://devtrunk.logiweb.de/kibana-TSI/bundles/vendors.bundle.js?v=16627:143:161619)
    at checkRespForFailure (https://devtrunk.logiweb.de/kibana-TSI/bundles/vendors.bundle.js?v=16627:143:160796)
    at https://devtrunk.logiweb.de/kibana-TSI/bundles/vendors.bundle.js?v=16627:137:20985
    at processQueue (https://devtrunk.logiweb.de/kibana-TSI/bundles/vendors.bundle.js?v=16627:116:132456)
    at https://devtrunk.logiweb.de/kibana-TSI/bundles/vendors.bundle.js?v=16627:116:133349
    at Scope.$digest (https://devtrunk.logiweb.de/kibana-TSI/bundles/vendors.bundle.js?v=16627:116:144239)
    at Scope.$apply (https://devtrunk.logiweb.de/kibana-TSI/bundles/vendors.bundle.js?v=16627:116:147018)
    at done (https://devtrunk.logiweb.de/kibana-TSI/bundles/vendors.bundle.js?v=16627:116:100026)
    at completeRequest (https://devtrunk.logiweb.de/kibana-TSI/bundles/vendors.bundle.js?v=16627:116:104697)
    at XMLHttpRequest.requestError (https://devtrunk.logiweb.de/kibana-TSI/bundles/vendors.bundle.js?v=16627:116:105545)

Browser's DevConsole is showing following errors:
https://pastebin.com/q4JaYMa5

Network Tab shows the following:

Kibana runs behind an Apache Webserver.

[chrisronline (Chris Roberson)]

Hi @asp,

I'd check the health of the ES cluster when that request is running. You might need to optimize on the ES side to support the type of query you are doing. I'd wager a guess that if you ran the same query (that Kibana is running for the visualization) against ES directly, you'd see more specific errors.