In some reports, “Failed to parse query [<filed>]” error is displayed. For instance, the following message says value passed for the field ‘entityType.keyword’ is empty.
In many reports, the query is based on the value selected from the drop-down menu (top left on the dashboard). If Elasticsearch does not have data for that report, then the default value in the drop-down menu shown as “None” which is used by Grafana to make a query. So, it throws such errors.
Verify why the data is missing in Elasticsearch and ensure that the necessary indices exist and also data is being ingested.