Can you check what the detailed error is in the 400 response from Meilisearch? It would be in the “Network” tab of the browser tools that you’re showing in your first screenshot.
You can also check if Studio is generating the Meilisearch user API keys correctly: Go to [CMS root]/api/content_search/v2/studio/ in your browser after being logged in. On Tutor devstacks, this URL is http://studio.local.openedx.io:8001/api/content_search/v2/studio/ but on your sandbox it will have a different domain.
That should return a response like this:
{"url":"http://meilisearch.local.openedx.io:7700","index_name":"tutor_studio_content","api_key":"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9..."}
If it’s not doing that, there is some configuration error with Meilisearch.
You can also try debugging Meilisearch directly, to check if data is actually stored in its index. To do this, go to https://meilisearch.sandbox-ng.abzt.de/ in your browser. To get the “Admin API Key” that you need to log in, run this tutor command: tutor config printvalue MEILISEARCH_API_KEY
If you see in that UI that the index doesn’t exist or is empty, fix it with this Tutor command: tutor [local|dev|k8s] exec cms ./manage.py cms reindex_studio --experimental . Just select the appropriate prefix (local, dev, or k8s) based on what type of deployment you’re using. (Too bad this is not just a tutor setting.) In fact, it’s probably a good idea to run that command anyways, to help with debugging. If there is some error going on, it should give a clear error message.
Hope this helps you get started!