Response from a test request either null oran empty array

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My question:
So I am not sure why but from my database from MongoDB I get as a response either null or an empty array. Strangely is that my db has at least 2 collections with data.
Does anyone know if it could be more to my export or is it an error occurring within the test request. It is a project from an online course. although it seems this has not happened to others.

Details (like screenshots):

How I found the problem: I sent requests and got answers such as in the screenshots.

This is how I have coded to export from mongoDB->

What else would I need to share in order for someone to suggest what might have I done wrong or coded