I suspect the filter is causing it to return 0 results. Does the data you inserted contain those metadata fields? If not, remove the filter section and try again.
Can you compare the curl request example when you click </> in Postman versus the curl command in the Pinecone playground/console? The below example is fake but shows the full request from my own Postman:
When the path following Pinecone’s service domain (.svc.us-east1-gcp.pinecone.io) is not valid, an HTTP 200 OK with an empty Body appears to be returned. (This assumes that the Api-Key is correctly set). In this case, even if the value of the POST Body is an invalid string (text/plain), an HTTP 200 is still returned.