After you have created a Kibana connection, you should validate its mappings to check for errors before you start exporting model data to Elasticsearch.
To validate your mapping, open the canvas menu
The validation process and its results are displayed in the Messages pane:
If validation is successful, you can start exporting your model data.
If the mapping contains errors or warnings, you should first address these before exporting your data. Any warnings will also be displayed in the mapping itself. An example is shown below. If you move your mouse pointer over the warning icon, a clarifying message will be shown.
As for the specific error shown in the above example, it can be ignored if you are only using the Kibana connection for exporting data. The ID field is only needed for importing data. Your metaobject should then also have an ID property that needs to be mapped to the "_id" field in the document definition.
To hide the validation results again, clickin the canvas menu.