Query error: Invalid query result data


I seem to be doing something wrong with my queries. The following error is shown, instead of the field in the panel: ‘Error in “gruppe” field, Invalid query result data’.

    label: Jugendgruppe
    type: select
    options: query
      fetch: pages.findByKey("jugendgruppen").children
      value: "{{page.title}}"
      text: "{{page.title}}"
    help: Bitte nur angeben, wenn die Veranstaltung nur für (d)eine Gruppe ist.

What’s wrong?

And how can I get a more detailed error message for debugging this myself?

You probably can’t use pages in blueprint query languages.

This will work:

fetch: site.find('jugendgruppen').children