Query by namespace and filter by metadata

Hello, good morning. I have created a namespace to store my products, and each product carries metadata with some special parameters for each product. When I query by namespace, it generates a correct result

But when I include a metadata filter, the result is empty. I have tried including MongoDB query language as it appears in the documentation, but the result is the same.

What can I do to obtain a result within the namespace and also filter by metadata? Is it possible?