While exporting and trying to test for request to see what data should appear, I got null and empty arrays

So to give you guys a better picture I am building an API where I have data from movies. I have a db with 4 collections. The problem I am facing is that when I test the requests I get an empty array & null responses.
What could be the issue I face? Does someone know if it is not exporting the data due to a db issue or is not connecting because of code?
I am using mongo & express.

Could it be the error within the code, my db or somehow Postman?